It keeps coming. PubSub is a RSS-based aggregator that allows you to sign up for search-term-based alerts, then emails you (or updates your RSS reader) when something is posted that matches your search. Signing up is painless, as it should be. It’s Google News Alerts for the RSS-osphere. Cool. Does Feedster or T’rati do this? I am starting to feel like keeping up with this stuff is a full time job. Man, we need a publication covering just this space…thanks to Dave Winer for the pointer.