Clamblogger cites a recent post by Darren Rowse about essential "hooks" to draw readers to your blog. One of the 7 hooks is thought leading content, another is personality of the blogger. I'm going to add another hook that doesn't necessarily fall into any of these thoughtful categories: Change Agent.
Some of the blogs that I come back to frequently, don't always have thought leading content (though they may) or great personality or any of the other hooks. But they do seem to have a quality or facility for bringing people together. Something like what Steven Van Yoder calls "centers of influence." It's not necessarily what they say but that they are connected to so many others that they help bring the world to you.
Here are some of the "change agent" blogs and sites I read. I definitely don't agree with everything they say and I have some skepticism about some of the concepts some espouse (such as "global oneness" at the experiencefestival site) but they seem to be on the leading edge of cultural change.