I've not explored Technorati much before and so I was mildly interested in the fact that they'll permit use of their charts on other sites. So, for example, here are the number of posts which mention WPF in the last 30 days:

Posts that contain WPF per day for the last 30 days.

Get your own chart!

Might be useful to put on your own web site to track topics you're interest in. Or then again, maybe not.