The reason people are looking at Erlang is not because its beautiful syntax, great documentation, or up-to-date libraries. Trust me. It's because the Erlang VM can run for long periods of time, scaling linearly across cores or processors filling the same niche that Java does right now on the server.
If you are resource constrained (pronounced "hosting providers charge obscene amounts of money for RAM") you don't want to run Java. You really don't want to run Java. It is an operational thing. I have ejabberd running on my personal server and am annoyed at the 13 megs resident it consumes after a month uptime. I could use OpenFire (Diego likes it.) but it sits at 40 megs at startup. Now this isn't apples to apples, they have different feature sets, but it feels about right.
Java has grown to fit the constraints in which the Java Customer Process members like it to be used: running Enterprise Services on fairly beefy hardware. If this is your situation, woot, go forth and win. It is, however, a situation ripe for disruption.