Sphere is a blogsearch engine that isn't even in public beta yet. The cat, though, is out of the bag, & they're in BusinessWeek:

Blog search involves a difficult calibration between relevance, authority and timeliness. I have the sense that Sphere has the tools to handle the job, but first needs to retwist a few of the knobs.

The new search engine has plenty of features that I like. At each link, you can click on the blogger to get profile information: Average number of posts per week and blogs recently linked to. I would also like to see the number of incoming links, to get an idea of the blog's reach.

I expect Sphere to make its grand debut shortly. Despite apparent kinks, it holds great promise. More details from Techcrunch and Om Malik.

Looks interesting, & there's always room for more search, esp. given the differences between the engines. I'll be interested to see how this turns out.