You can't reach it now, but danny points to the BlogPuppyFuckWit™ Steve Rubel who's noticed a previously working url at: test.rss.search.yahoo.com.

Wooohoo! the power of a major SE on blog search? smashing...

Presumably they won't do it half heartedly and will use their recent aquisition of blo.gs ping service to power, or at least add to the new engine..

Can't wait...