Part of the problem with people based following models on social networks is that you follow the whole person so see everything they post whether it is relevant to you or not. There is no filtering system.
He goes on to mention that blogrolls that also supply an OPML file make it quick to subscribe via RSS to all of the blogs in the roll. Then, that person can determine whether or not to keep each subscription based on the value they get from them.
I can see that. But, I still go back to my original thought on this. If I subscribe to a bunch of blogs (and I do) and then I link to individual posts that I think are interesting, then I'm acting as a curator for my subscribers. This is why Kottke, Daring Fireball, and Waxy are so popular. They highlight some of the most interesting content, discussions, or resources they've found on the web. I do not intend to try to be as focused as Daring Fireball or as prolific as Kottke, but if I find something interesting I enjoy linking to them and giving my thoughts. If I really think something is worth discussing then I will link to it in an individual post.
If you subscribe to my blog and notice I'm routinely linking to a particular source (like Colin Walker) you may consider hopping over to your nearest feed reader and subscribing to his site as well.
Walker also mentions that anecdotal evidence suggests that people using RSS or JSON Feed to subscribe to blogs is on the rise. I'm seeing that too. And I'm very happy about it.