While I agree that personalization is the way to go, I think that most users would like more control over personalization rather than rely on some mysterious collaborative filtering algorithm. Moreover, people read blogs for a reason: they actually want to see all the postings from those blogs, not potentially interesting postings from unknown blogs. Consequently, instead of having a collaborative filtering algorithm, one might use a social network approach. Moreover, rather than recommending individual posts, the user would instead build a set of trusted sources (users and/or feeds) via the social network.