[ecolak]

I like the write-up, but I disagree with the reasoning to avoid STM. It sounds a lot like "avoid ConcurrentHashMap in Java". It's true that web applications mostly persist their data in a database or some other persistent structure, and obviously an STM or a ConcurrentHashMap would not do you any good for that. However; if you are working with in-memory data, then STM is a very valuable tool just like ConcurrenthHashMap is.

[brunchboy]

That was going to be my point as well. My “production” application runs light shows for electronic music events. The only state that matters is in-memory in the STM. There is no database. STM works wonderfully in the rare cases where there are multiple values which need to be changed in a coordinated way.