Yahoo! Answers hits Europe
This is my favourite bit:
Questioners impressed with an answer can rate that person as an expert in a particular field. If other people also obtain good answers from this individual, it creates a league table of the best "answerers" in categories such as food and drink, or beauty and style. Some Yahoo! Answers users in the US have already gained a reputation as providers of trustworthy responses, rather like PowerSellers on the eBay auction site.
Reputation for providing sound advice in a particular subject is an excellent method of ensuring committment and weeding out griefers. It also provides an outlet for people with Mastermind-like knowledge of something. I wonder if there will be user profiles which say things like "Knows a lot about pirates, not much about soup recipes". I'm envisaging character selection screens in beat-em-ups.
Bringing back the social. Superb.