I don't think that's a solution because it assumes everyone would agree that X is for personal posts, Y for professonal, etc. I don't think that kind of agreement will ever come about. I believe in filters but all the ones currently out there aren't at the right level of granularity. It's not about the service, the person, the list, or the search result. The update itself is the right granularity to consider for relevance (as this blog post shows).