Technorati has started an effort to catalogue bloggers by topic. This is welcome, but Technorati's solution so far is not really working that well. The reason is that bloggers - rather than users - choose their tags. This makes it really easy for a blogger like me to claim that I am #1 for knitting, even though I have never touched the subject. I personally wouldn't do this since it's dishonest, still, there's nothing in the current Technorati system that would stop a blogger with a lot of links from trying.
A better way to find a blogger's "beat" is through keyword density. These tools identify the keywords that are most dominant ones on a given Web site. For example, here's a sample report for MarketingVOX.
