With a few spare cycles, I enjoyed working through back entries of Bob Wyman's weblog. Wyman is the chief public face of PubSub.com. I particularly like how he tries to position PubSub.com as not a traditional search engine, although I find "prospective search" a bit tortured.
"Browse" is typically placed as the opposite of search, but I'm thinking "watch" might be more appropriate. And PubSub is one of the few, good, leading edge watch engines we have.
And just to be greedy I'd be all over any more technical details on how PubSub does that many matches.