Thanks to a question posed by Lyle Johnson, I've posted a few suggestions on how to keep your RubyForge mailing lists neat and tidy in the RubyForge admin checklist/guide/thing. It's down near the bottom of that page - see item # thirteen. I'll probably send around a mass mailing to all RubyForge list admins with this information in it as well. And if you have any other suggestions for list cleaning, please let me know.
On a related note, if you want to help keep RubyForge quick and snappy, there are a few other tips there for doing that, like turning off features you aren't using - surveys, task tracker, and so on. And of course if you started a project but never really got traction on it, feel free to post a support request and I can shut it down for you to save space and clutter and whatnot. Every little bit helps.... with almost 1200 projects and 4800 users, RubyForge is a busy system; thanks much!