[brandoncapecci]

The amount of people I know who use functional frameworks (say Underscore) to build things but don't really know much about functional programming is astonishing. To be fair, a lot of frameworks that espouse "functional programming" do so just because it's popular and really push imperative concepts instead so it's easy to be confused on the "right way".

[jarrett]

I love Underscore (and Haskell), but I wouldn't consider Underscore an FRP framework at all. It's functional, yes, in the sense that it provides some of the most common FP operations like map, filter, etc, using lambdas. But I don't see the reactive part. Maybe there's some kind of reactive feature tucked away in Underscore's rather large feature set, but I haven't seen it, and it's certainly not core to the library.

[seanmcdirmid]

Databinding is not FRP, but you can do a lot of FRP things with it. If you are into WPF, check out Bling:

http://bling.codeplex.com/

We are able to subvert WPF databinding mechanisms to allow bindings to expressions as well as functions. The act of binding itself is still very imperative (and so, not very FRP-ish), but beyond that the programming styles are quite similar.