Up-votes and five star scales are just early experiments in recommendations. "Also bought" is an even earlier one. It clearly works in silos (Reddit, Netflix, Amazon) and, perhaps covertly, on the open web (Page Rank, personalized search), but there is still a lot more research to be done. I'm excited about it :-)

It works here and on Amazon, etc. because there is so much noise that most people only want to see the highlights. On Facebook, most people want to see every update from the friends (except all the junk apps like Farmville). I'd rather have a feed that shows me everything except stuff that's been downvoted by people picking "hide this".

I have my Facebook statuses feed piped to RSS and then filtering out the people that write the most useless stuff. That folder in my mail client currently has 1347 unread statuses, and that's just since the last time I marked "set all as read" a couple months back. I seriously question if people want to see everything. And I have a lowly 115 friends. Now take into account that more and more data is being pushed through that channel and I think it becomes obvious that eventually "show me everything" becomes virtually useless at some point in the future.