I just tried the Technorati index - my, but isn't there a lot of rubbish out there!
I looked at the home and garden section first - hoping to find a useful gardening blog by someone with some knowledge (for this, and for re-use by my RHS students). No sign of anything like it - lots of interiors and 'look how big this pumpkin is!' but no real knowledge.
However once I tried the technical blogs I had more luck - this from acidlabs is interesting, although more about engagement through ICT for government (among other things) than an educational focus.
It took too long to find it though so this is the only one I'm going to post.
I think blogs are like the web in general - there's a lot of information but you need to pick it out of the junk - only even more so.
Vikki