Or a new IceRocket or Daypop.
I was hanging about with my fellow bloggers and we were whining (much as bloggers do) about the lack of blog search engines these days. RSS or spider this seems to be a niche that nobody is covering: search engine results only from blogs. (Blog directories just don't cut it.)
I have no idea how a spidering engine could distinguish between a blog and a non-blog website but it must be possible. I guess it would be easier for an RSS engine, but not as deep.
Anyway, it's a niche.