This example from the Yesod book is now up-to-date with version 1.2 of Yesod. It includes more prose to explain what's going on, and is a pretty good overview of a number of the more advanced concepts in Yesod.
Are any of the Yesod ninjas looking into this? I am very curious to know whether they think these results represent a fair estimation of where Yesod stands relative to the other frameworks. Also they seem to have quite a broad definition of 'framework'. Would Warp qualify?
Does anyone have any experience with wai-eventsource (http://goo.gl/q8yyO) and can tell me how reliable it is? On my test server, I got some trouble with the connection, and now suddenly it works again. I use it in the exact same way as in the Chat Example for yesod (http://goo.gl/189hc).