Russell makes the assumption that linking to someone's blog is some kind of unconditional recommendation. Far from it! If you look at the standard version of my blog you'll see I've just added the text "Blogs I read", to clarify this. I don't recommend any of these for anyone's reading but my own. In fact, some of this stuff I very strenuously disagree with, but I find it interesting to hear ideas that are well argued, passionately held but that I disagree with. It's an intellectually challenging thing to do.
However, where a blogroll is interesting is similar to the way I browse a person's book and CD shelves when I visit their homes. You can learn a lot about people by what they read, listen to, watch and otherwise consume. It's interesting and gives you more of an understanding of the person.
Similarly, I quite enjoy the various Planets I read because I get to read more about people. I read about their cats, their struggles with the landlord, their healthy problems, all kinds of stuff. While the Planets themselves represent a particular interest, the people posting to them are human beings too, and have more in their life than just the interest. This is a good thing.
Of course, the shadowy cabal who run Planet Linux Australia clearly don't agree with this thinking, by silently dropping all of my blog except the geek category.