Threadsy might have solved much of what you're looking for; unfortunately, they shut down.

http://news.cnet.com/8301-33200_3-57354466-290/threadsys-gon...

I would love to see someone else try to build this. Filtering options would need to be robust and flexible to combat potential noise and info overload. I could see marketers being an easy initial niche customer. General consumers, not so much. But I'd sure pay for something like this.