No, it's not the number of hits a blog gets. It's the number of comments/trackbacks a blog gets.

Here's a good example: Bruce Schneier reporting a possible break of a security technology. The same news about a Chinese research team having found a collision (or whatever -- I'm far from a hardcore security type myself) in the SHA-1 hashing algorithm has been reported by probably hundreds of websites across the Internet and yet it's Bruce's blog that gets all the action.