I haven't looked at any data on following, but at least I follow most new people based on Twitter's recommendations, or by directly looking at who my friends fo

I haven't looked at any data on following, but at least I follow most new people based on Twitter's recommendations, or by directly looking at who my friends follow. But anyway, I don't see what that has to do with my point. Following people is just the first step. After you've followed them, you read and interact with them. An aggregator provides a place for doing that. In fact, you don't even need to follow anyone to interact with them. I don't see how you can compare it to email either. Email is completely private. Twitter is completely public by default, unless you explicitly use a private message (DM). It's like saying what's the point of Hacker News, when we can email each others links to our blog posts. The public forum is the point.