I'm not an expert, just interested in the subject.

I thought of an idea, and this is completely fresh so take it with a grain of salt, but you could use social data from all users subscribed to the same feed to modify the prior probability that any given post was interesting, and then use each individual's data to modify the conditional posterior probability terms.

I'm not sure how effective it would be, but it would create a hybrid sort of classifier that might be interesting.

I'm studying natural language processing this quarter, so I'll let you know in three months if I come up with something more clever.