I have "tried it & stopped". I only tried it to check out webmachine, which appears to the be only web framework in existence that is not stupid and terrible. I stopped because I was done trying webmachine, and went back to my normal language that is much nicer than erlang (haskell).
I don't think my experience with erlang has anything to do with the reasons it isn't more popular though. The biggest thing I see is the lack of module/library/package management. CPAN was a big deal. It is now expected that every language have their own CPAN. I think the lack of one is a huge problem for any language, erlang being a good example. I think it is also a big reason that ocaml and haskell went from being "ocaml is the more commonly used one" to "haskell has ten times the userbase of ocaml".
I don't think my experience with erlang has anything to do with the reasons it isn't more popular though. The biggest thing I see is the lack of module/library/package management. CPAN was a big deal. It is now expected that every language have their own CPAN. I think the lack of one is a huge problem for any language, erlang being a good example. I think it is also a big reason that ocaml and haskell went from being "ocaml is the more commonly used one" to "haskell has ten times the userbase of ocaml".