Bumpzee communities provide topic focused blog feeds, tools for blogs and more. I have created communities for science and for engineering. They offer some of the common tools such as highlighting posts community members have voted up (bumped). Blog owners can add there blogs to bumpzee and the communities. Bumpzee offers tools to track blog statistics (others offer similar things, of course, for example: mybloglog, google analytics, feedburner) with interactive features (like showing what Bumpzee members are viewing the blog, most popular posts on your blog, most poplular posts in your community…).

Related: Science and Engineering blog directory - Curious Cat Science and Engineering Search - Science and Engineering Education Blog Directory