Service to monitor phpBB, vbulletin, ubb and other forums?

I’m looking for a “Google Alerts”-like service that’ll notify me when certain keywords appear in certain forums (example: I’d like to be notified everytime someone posts ‘snapstream’ or ‘beyondtv’ or ‘beyond tv’ on byopvr.com). Or I’d like to be notified when a particular user makes a post within a particular forum.

Something like this would make it a lot easier for me to track and monitor conversations in the forum-o-sphere (yes, that is a term that I just made-up… 1:15pm central time, Sunday, September 10, 2006 — you heard it here first!). Forums are pretty darn popular, at least they are for us over at SnapStream and my sense for it is they are more practical and accessible to the general population than blogs are. ie random Joe customer is more likely to post something in a company’s forum or in a community forum than he is to create a blog and make a posting about it there. Even if he already had a personal blog, he’s probably still post to a company or community forum, knowing that he’s likely to get more traffic and responses that way.

If a service like this doesn’t exist, it’ll be one of those “shit, why doesn’t this service exist?” moments for me. With blog search being such a hot area, Technorati and Google duking it out, how can everyone be missing out on being able to search and track conversations in the forum-o-sphere?