The Luxembourg-based Wikio has secured funding for €4 million ($5.3 million).
Wikio is like Digg + Google News + Technorati, still in its early phases but promises to lead the way in European Web 2.0 search technologies.

Wikio, launched in France last June, and currently operating sites in France, United States, Germany, Italy and Spain, is [...]

Technorati is a great blogsearch.   There, I said it.  I like Technorati.  However, Technorati has hit some bad spots of late.  They’ve lost employees, been overrun by splogs, and have had some recent acquisition deals go bad.
But, they just got substantial funding, so all is good for Technorati for the time being, I suppose.
Blog search [...]

Goldman, former Sr VP of Corporate and Business Development at Movielink and founder/CEO of Broadband Sports, Inc., has taken the position of President a Feedster.  
“Feedster is well positioned to expand its leadership in search and syndication.” said Mr. Goldman. “With 41 million blogs and feeds being searched dynamically, Feedster provides consumers with the best [...]

Octora is a beta RSS search engine.  You can input a keyword (tag) and the search engine will find all relevant RSS feeds for the keyword.
Try Octora at octora.com.