YOUTUBE qI_g07C_Q5I Martin Fowler presents "Introduction to NoSQL"
Fowler talks about his book, NoSQL Distilled which describes the rest of this in topic in depth.
In this presentation, Fowler gives an overview of NoSQL databases. He creates a classification for them, then talks about locking and acid tradeoffs.
He talks about how databases which are distributed rose to deal with scaling hardware which is expensive.
33:43 Fowler presenting offline locks
Most of the time you aren't trading off consistency vs availability, a lot of the time what you're doing is trading off consistency vs response time. This is a business decision.
He argues that integration across the same database locked in these SQL solutions. And this integration pain is still happening in NoSQL, we're doing it with APIs. This is arguably a better solution because you don't want to deal with the inconsistencies.
51:25 Fowler describes how an application may be composed of many databases depending on the domain
CAP Theorem boiled down: when there's a partition would you like to be Consistent or Available? You can break this out depending on the operation you want to do.
When talking about Consistency and Availability this is a database dealing with the general concurrency tradeoff between Safety and Liveliness 
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