Haskell is actually awesome for something like Comet or just about anything where concurrency is involved. I'm launching a small Haskell-based product called E

Haskell is actually awesome for something like Comet or just about anything where concurrency is involved. I'm launching a small Haskell-based product called EventSource HQ (http://www.eventsourcehq.com http://www.eventsourcehq.com) taking advantage of just this. Handling state across threads in Haskell is not a problem at all. Haskell is not bad or complex when it comes to mutable state, it's just very explicit about it. When it comes to doing stuff the involves multiple threads this is a huge advantage. Haskell is complex in the sense that it brings a whole bunch of new abstractions to the table that can take a lot of work to get a hold of. But while this can make for a steep learning curve, it also comes with a huge payoff, since these abstractions are very powerful. Stuff like Iteratee's and Enumerators or the newer Conduits can be tough to wrap your head around, but once you do the power of composable abstractions over IO streams can be extremely useful.