I thought since this is a web forum that saying "... in the context of web development" was superfluous.
Well, XML or Perl aren't limited too web development, and I'd consider any question with them on topic.

This Ruby sounds interesting, is that likely to be big for web dev?
I don't know. I'm expecting it to put some serious heat on Perl and Python for *nix scripting language of choice in a couple years. If someone makes Apache mod_ruby I'm sure it'll be.