Additionally, I think that Haskell really has to offer something over most other FP languages. Many features of dynamic impure FP languages have already been ported to languages such as Ruby or Python. What Haskell provides over, say Lisp, is exceptionally strong typing and isolation of side-effects. This is a quality that cannot be ported to mainstream languages easily.

So, why didn't Haskell become more popular earlier? I think that's simple: the GHC compilers has improved tremendously over the past years, Hackage has grown considerably, and there are now more books oriented at practical programming.

After spending some time exploring different functional languages, if FP does make it at all - my money would be on Haskell. There is something to be said for focused languages that does one thing but does it really well, and the feeling of security when a certain style is enforced over a codebase.

I probably wouldn't use it for anything today, but in another couple years maybe. The ecosystem seems like it's reaching critical mass.

I think Clojure is ready right now. For "standalone" languages haskell seams to be on a good way, some people are allready doing start ups with it.

Actually most Lisps offer optional means of static verification and static typing for when its necessary. Furthermore, Lisps have vital metaprogramming features that Haskell lacks which are essential for symbolic AI applications.

5. Code-hipsters on HN ;-)

A nice way of putting it would be "FP became better at marketing"