My colleague at Harvard, Matt Welsh, has started a new blog, Volatile and Decentralized. It will be focused on systems -- primarily sensor networks -- but will also have all of his other interesting insights on teaching, students, being an associate professor, Harvard, etc. Go check out the first few posts!
I've often wondered why more systems people don't blog. I think I asked someone once (Jennifer Rexford?) and was told, "We're too busy." I'm glad Matt's not too busy to share his work and insights with all of us.