Fixes from review.

Added a more prominant warning for #68 about SimpleDB being mostly obsolete.
(Probably want more detail though.)

README.md

@@ -111,7 +111,7 @@ General Information
 	-	and you can afford, manage, or negotiate its somewhat higher costs
 	-	... then AWS is likely a good option for your company.
 -	Each of those reasons above might point to situations where other services are preferable. In practice, many, if not most, tech startups as well as a number of modern large companies can or already do benefit from using AWS. Many large enterprises are partly migrating internal infrastructure to Azure, Google Cloud, and AWS.
--	**Costs:** Billing and cost management are such big topics we have [an entire section on this](#billing-and-cost-management).
+-	**Costs:** Billing and cost management are such big topics that we have [an entire section on this](#billing-and-cost-management).
 -	🔹**EC2 vs. other services:** Most users of AWS are most familiar with [EC2](#ec2), AWS’ flagship virtual server product, and possibly a few others like S3 and ELBs. But AWS products now extend far beyond basic IaaS, and often companies do not properly understand or appreciate all the many AWS services and how they can be applied, due to the [sharply growing](#which-services-to-use) number of services, their novelty and complexity, branding confusion, and fear of ⛓lock-in to proprietary AWS technology. Although a bit daunting, it’s important for technical decision-makers in companies to understand the breadth of the AWS services and make informed decisions. (We hope this guide will help.)
 -	🚪**AWS vs. other cloud providers:** While AWS is the dominant IaaS provider (31% market share in [this 2016 estimate](https://www.srgresearch.com/articles/aws-remains-dominant-despite-microsoft-and-google-growth-surges)), there is significant competition and alternatives that are better suited to some companies:
 	-	The most significant direct competitor is [**Google Cloud**](https://cloud.google.com/). It arrived later to market than AWS, but has vast resources and is now used widely by many companies, including a few large ones. It is gaining market share. Not all AWS services have similar or analogous services in Google Cloud. And vice versa: In particular Google offers some more advanced machine learning-based services like the [Vision](https://cloud.google.com/vision/), [Speech](https://cloud.google.com/speech/), and [Natural Language](https://cloud.google.com/natural-language/) APIs. It’s not common to switch once you’re up and running, but it does happen: [Spotify migrated](http://www.wsj.com/articles/google-cloud-lures-amazon-web-services-customer-spotify-1456270951) from AWS to Google Cloud. There is more discussion [on Quora](https://www.quora.com/What-are-the-reasons-to-choose-AWS-over-Google-Cloud-or-vice-versa-for-a-high-traffic-web-application) about relative benefits.
@@ -160,14 +160,14 @@ General Information
 	-	[EMR](#emr): Managed Hadoop
 	-	[Elasticsearch](https://aws.amazon.com/elasticsearch-service/): Managed Elasticsearch
 	-	[ElastiCache](https://aws.amazon.com/elasticache/): Managed Redis and Memcached
--	**Optional but important infrastructure:** These are key and useful infrastructure that are less widely known used. You may have legitimate reasons to prefer alternatives, so evaluate with care you to be sure they fit your needs:
+-	**Optional but important infrastructure:** These are key and useful infrastructure components that are less widely known and used. You may have legitimate reasons to prefer alternatives, so evaluate with care you to be sure they fit your needs:
 	-	⛓[Lambda](#lambda): Running small, fully managed tasks “serverless”
 	-	[CloudTrail](https://aws.amazon.com/cloudtrail/): AWS API logging and audit (often neglected but important)
 	-	⛓🕍[CloudFormation](#cloudformation): Templatized configuration of collections of AWS resources
 	-	🕍[Elastic Beanstalk](https://aws.amazon.com/elasticbeanstalk/): Fully managed (PaaS) deployment of packaged Java, .NET, PHP, Node.js, Python, Ruby, Go, and Docker applications
 	-	🐥⛓[EFS](https://aws.amazon.com/efs/): Network filesystem
-	-	⛓🕍[ECS](#ecs): Docker container/cluster management. Note Docker can be used directly, without ECS.
+	-	⛓🕍[ECS](#ecs): Docker container/cluster management (note Docker can also be used directly, without ECS)
-	-	⛓[ECR](https://aws.amazon.com/ecr/): Hosted private Docker registry.
+	-	⛓[ECR](https://aws.amazon.com/ecr/): Hosted private Docker registry
 	-	🐥[Config](https://aws.amazon.com/config/): AWS configuration inventory, history, change notifications
 -	**Special-purpose infrastructure:** These services are focused on specific use cases and should be evaluated if they apply to your situation. Many also are proprietary architectures, so tend to tie you to AWS.
 	-	⛓[DynamoDB](#dynamodb): Low-latency NoSQL key-value store
@@ -213,7 +213,7 @@ General Information
 
 ### Tools and Services Market Landscape
 
-There are now enough cloud and “big data” enterprise companies and products few can keep up with the market landscape. (See the [Big Data Evolving Landscape – 2016](https://practicalanalytics.co/2016/02/09/big-data-evolving-landscape-2016/) for one attempt at this.)
+There are now enough cloud and “big data” enterprise companies and products that few can keep up with the market landscape. (See the [Big Data Evolving Landscape – 2016](https://practicalanalytics.co/2016/02/09/big-data-evolving-landscape-2016/) for one attempt at this.)
 
 We’ve assembled a landscape of a few of the services. This is far from complete, but tries to emphasize services that are popular with AWS practitioners — services that specifically help with AWS, or a complementary, or tools almost anyone using AWS must learn.
 
@@ -318,7 +318,7 @@ It’s important to know the maturity of each AWS product. Here is a mostly comp
 | [CloudWatch](https://aws.amazon.com/releasenotes/CloudWatch?browse=1)                                      | 2009-05          | General      |
 | [CloudFront](https://aws.amazon.com/releasenotes/CloudFront?browse=1)                                      | 2008-11          | General      |
 | [Fulfillment Web Service](https://aws.amazon.com/releasenotes/Amazon-FWS?browse=1)                         | 2008-03          | Obsolete?    |
-| [SimpleDB](https://aws.amazon.com/releasenotes/Amazon-SimpleDB?browse=1)                                   | 2007-12          | Obsolete     |
+| [SimpleDB](https://aws.amazon.com/releasenotes/Amazon-SimpleDB?browse=1)                                   | 2007-12          | ⚠️Nearly obsolete     |
 | [DevPay](https://aws.amazon.com/releasenotes/DevPay?browse=1)                                              | 2007-12          | General      |
 | [Flexible Payments Service](https://aws.amazon.com/releasenotes/Amazon-FPS?browse=1)                       | 2007-08          | Retired      |
 | [EC2](https://aws.amazon.com/releasenotes/Amazon-EC2?browse=1)                                             | 2006-08          | General      |
@@ -514,7 +514,7 @@ We cover security basics first, since configuring user accounts is something you
 -	**Use KMS for managing keys**: AWS offers [KMS](#kms) for securely managing encryption keys, which is usually a far better option than handling key security yourself. See [below](#kms).
 -	[**AWS WAF**](https://aws.amazon.com/waf) is a web application firewall to help you protect your applications from common attack patterns.
 -	**Security auditing:**
-	-	[Security Monkey](https://github.com/Netflix/security_monkey) is an open source tool to assist with secuirty audits.
+	-	[Security Monkey](https://github.com/Netflix/security_monkey) is an open source tool that is designed to assist with security audits.
 	-	🔹**Export and audit security settings:** You can audit security policies simply by exporting settings using AWS APIs, e.g. using a Boto script like [SecConfig.py](https://gist.github.com/jlevy/cce1b44fc24f94599d0a4b3e613cc15d) (from [this 2013 talk](http://www.slideshare.net/AmazonWebServices/intrusion-detection-in-the-cloud-sec402-aws-reinvent-2013)) and then reviewing and monitoring changes manually or automatically.
 
 ### Security and IAM Gotchas and Limitations
@@ -1173,7 +1173,7 @@ EMR
 ### EMR Tips
 
 -	EMR relies on many versions of Hadoop and other supporting software. Be sure to check [which versions are in use](https://docs.aws.amazon.com/ElasticMapReduce/latest/ReleaseGuide/emr-release-components.html).
--	💸❗**EMR costs** can pile up quickly since it involves lots of instances, efficiency can be poor depending on cluster configuration and choice of workload, and accidents like hung jobs are costly. See the [section on EC2 cost management](#ec2-cost-management), especially the tips there about spot instances and avoiding hourly billing. [This blog post](http://engineering.bloomreach.com/strategies-for-reducing-your-amazon-emr-costs/) has additional tips.
+-	💸❗**EMR costs** can pile up quickly since it involves lots of instances, efficiency can be poor depending on cluster configuration and choice of workload, and accidents like hung jobs are costly. See the [section on EC2 cost management](#ec2-cost-management), especially the tips there about Spot instances and avoiding hourly billing. [This blog post](http://engineering.bloomreach.com/strategies-for-reducing-your-amazon-emr-costs/) has additional tips.
 -	⏱Off-the-shelf EMR and Hadoop can have significant overhead when compared with efficient processing on a single machine. If your data is small and performance matters, you may wish to consider alternatives, as [this post](http://aadrake.com/command-line-tools-can-be-235x-faster-than-your-hadoop-cluster.html) illustrates.
 -	Python programmers may want to take a look at Yelp’s [mrjob](https://github.com/Yelp/mrjob).
 -	It takes time to tune performance of EMR jobs, which is why third-party services such as [Qubole’s data service](https://www.qubole.com/mapreduce-as-a-service/) are gaining popularity as ways to improve performance or reduce costs.
@@ -1194,7 +1194,7 @@ This section covers tips and information on achieving [high availability](https:
 	-	The bulk of outages in AWS services affect one zone only. There have been rare outages affecting multiple zones simultaneously (for example, the [great EBS failure of 2011](http://aws.amazon.com/message/65648/)) but in general most customers’ outages are due to using only a single AZ for some infrastructure.
 	-	Consequently, design your architecture to minimize the impact of AZ outages, especially single-zone outages.
 	-	Deploy key infrastructure across at least two or three AZs. Replicating a single resource across more than three zones often won’t make sense if you have other backup mechanisms in place, like S3 snapshots.
-	-	A second or third AZ should significantly improve availability, but additional reliability of 4 or more AZs may not justify the costs or complexity (unless you have other reasons like capacity or spot market prices).
+	-	A second or third AZ should significantly improve availability, but additional reliability of 4 or more AZs may not justify the costs or complexity (unless you have other reasons like capacity or Spot market prices).
 	-	💸Watch out for **cross-AZ traffic costs**. This can be an unpleasant surprise in architectures with large volume of traffic crossing AZ boundaries.
 	-	Deploy instances evenly across all available AZs, so that only a minimal fraction of your capacity is lost in case of an AZ outage.
 	-	If your architecture has single points of failure, put all of them into a single AZ. This may seem counter-intuitive, but it minimizes the likelihood of any one SPOF to go down on an outage of a single AZ.
@@ -1230,21 +1230,21 @@ Billing and Cost Management
 
 -	With EC2, there is a trade-off between engineering effort (more analysis, more tools, more complex architectures) and spend rate on AWS. If your EC2 costs are small, many of the efforts here are not worth the engineering time required to make them work. But once you know your costs will be growing in excess of an engineer’s salary, serious investment is often worthwhile.
 -	🔹**Spot instances:**
-	-	EC2 [spot instances](https://aws.amazon.com/ec2/spot/) are a way to get EC2 resources at significant discount — often many times cheaper than standard on-demand prices — if you’re willing to accept the possibility that they be terminated with little to no warning.
+	-	EC2 [Spot instances](https://aws.amazon.com/ec2/spot/) are a way to get EC2 resources at significant discount — often many times cheaper than standard on-demand prices — if you’re willing to accept the possibility that they be terminated with little to no warning.
-	-	Use spot instances for potentially very significant discounts whenever you can use resources that may be restarted and don’t maintain long-term state.
+	-	Use Spot instances for potentially very significant discounts whenever you can use resources that may be restarted and don’t maintain long-term state.
 	-	The huge savings that you can get with Spot come at the cost of a significant increase in complexity when provisioning and reasoning about the availability of compute capacity.
-	-	Amazon maintains spot prices at a market-driven fluctuating level, based on their inventory of unused capacity. Prices are typically low but can [spike](http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-spot-limits.html#spot-bid-limit) very high. See the [price history](http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-spot-instances-history.html) to get a sense for this.
+	-	Amazon maintains Spot prices at a market-driven fluctuating level, based on their inventory of unused capacity. Prices are typically low but can [spike](http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-spot-limits.html#spot-bid-limit) very high. See the [price history](http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-spot-instances-history.html) to get a sense for this.
 	-	You set a bid price high to indicate how high you’re willing to pay, but you only pay the going rate, not the bid rate. If the market rate exceeds the bid, your instance may be terminated.
 	-	Prices are per instance type and per availability zone. The same instance type may have wildly different price in different zones at the same time. Different instance types can have very different prices, even for similarly powered instance types in the same zone.
 	-	Compare prices across instance types for better deals.
-	-	Use spot instances whenever possible. Setting a high bid price will assure your machines stay up the vast majority of the time, at a fraction of the price of normal instances.
+	-	Use Spot instances whenever possible. Setting a high bid price will assure your machines stay up the vast majority of the time, at a fraction of the price of normal instances.
-	-	Get notified up to two minutes before price-triggered shutdown by polling [your spot instances’ metadata](https://aws.amazon.com/blogs/aws/new-ec2-spot-instance-termination-notices/).
+	-	Get notified up to two minutes before price-triggered shutdown by polling [your Spot instances’ metadata](https://aws.amazon.com/blogs/aws/new-ec2-spot-instance-termination-notices/).
 	-	Make sure your usage profile works well for Spot before investing heavily in tools to manage a particular configuration.
 -	**Spot fleet:**
-	-	You can realize even bigger cost reductions at the same time as improvements to fleet stability relative to regular spot usage by using [Spot fleet](http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/spot-fleet.html) to bid on instances across instance types, availability zones, and (through multiple Spot Fleet Requests) regions.
+	-	You can realize even bigger cost reductions at the same time as improvements to fleet stability relative to regular Spot usage by using [Spot fleet](http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/spot-fleet.html) to bid on instances across instance types, availability zones, and (through multiple Spot Fleet Requests) regions.
-	-	Spot fleet targets maintaining a specified (and weighted-by-instance-type) total capacity across a cluster of servers. If the spot price of one instance type and availability zone combination rises above the weighted bid, it will rotate running instances out and bring up new ones of another type and location up in order to maintain the target capacity without going over target cluster cost.
+	-	Spot fleet targets maintaining a specified (and weighted-by-instance-type) total capacity across a cluster of servers. If the Spot price of one instance type and availability zone combination rises above the weighted bid, it will rotate running instances out and bring up new ones of another type and location up in order to maintain the target capacity without going over target cluster cost.
 -	**Reserved Instances** allow you to get significant discounts on EC2 compute hours in return for a commitment to pay for instance hours of a specific instance type in a specific AWS region and availability zone for a pre-established time frame (1 or 3 years). Further discounts can be realized through “partial” or “all upfront” payment options.
-	-	Consider using Reserved Instances when you can predict your longer-term compute needs and need a stronger guarantee of compute availability and continuity than the (typically cheaper) spot market can provide. However be aware that if your architecture changes your computing needs may change as well so long term contracts can seem attractive but may turn out to be cumbersome.
+	-	Consider using Reserved Instances when you can predict your longer-term compute needs and need a stronger guarantee of compute availability and continuity than the (typically cheaper) Spot market can provide. However be aware that if your architecture changes your computing needs may change as well so long term contracts can seem attractive but may turn out to be cumbersome.
 	-	Instance reservations are not tied to specific EC2 instances - they are applied at the billing level to eligible compute hours as they are consumed across all of the instances in an account.
 -	**Hourly billing waste:** EC2 instances are [billed in instance-hours](https://aws.amazon.com/ec2/faqs/#How_will_I_be_charged_and_billed_for_my_use_of_Amazon_EC2) — rounded up to the nearest full hour! For long-lived instances, this is not a big worry, but for large transient deployments, like EMR jobs or test deployments, this can be a significant expense. Never deploy many instances and terminate them after only a few minutes. In fact, if transient instances are part of your regular processing workflow, you should put in protections or alerts to check for this kind of waste.
 -	If you have multiple AWS accounts and have configured them to roll charges up to one account using the “Consolidated Billing” feature, you can expect *unused* Reserved Instance hours from one account to be applied to matching (region, availability zone, instance type) compute hours from another account.