Bill Clementson has posted on Concurrent Programming, and how a language that can effectively support concurrency may be able to displace current widely-used languages in which that support is flawed.

A language he focused on was Erlang, but I was reminded of another language, Cilk. Cilk is a variant of C with features for spawning parallel computations (Cilk programs become equivalent serial C programs when the new Cilk keywords are removed). Its implementation has an effective and highly cool 'work stealing' scheduler for allocating large numbers of fine grained tasks among a smaller set of worker threads.

I don't know if Cilk would be suitable for something like a web server, but for highly parallel computational tasks programs it has done well. A team using Cilk won the ICFP'98 Programming Contest, and Cilkchess, a chess program written in Cilk, came in 4th (out of 30 programs) in the 1999 World Computer Chess Championship.