Straight from the Google blog is the new that Google Answers is closing down, with the acceptance of new questions stop later this week. The surprising admission that they only had about 800 users replying to questions in 4 years of operation does not make this any less of a blow to the company, who downplay Answers to being just a "great experiment". In comparison, competitor services such as Yahoo Answers and Windows Live QnA seem to be flourishing.
Yahoo Answers has recently undergone a large advertising campaign in the UK, and has heavily promoted celebrity questions both here and in the USA. Currently they have Oprah asking the question "If you were given $1,000 to change the life of a perfect stranger, what would you do?" with the number of answers standing at over 33,000 at the time of posting.
QnA is less established, but one that seems to be building a solid community. Unlike Google Answers, which was not promoted on Google.com, QnA is linked on the Windows Live Search homepage, driving users to the service. The QnA modules that can be added to Windows Live Spaces have also helped with its growth, but a lack of rewards for top users may become an issue as the service develops.
Of course this doesn't have much effect on the current search rankings, (Live Search share drops) but it has reinforced the idea that social search is perhaps Google's biggest weakness.
Update: Minor correction made clarifying what the figure of "more than 800" refers to.