Yahoo! Answers (http://answers.yahoo.com/) is a relatively new Yahoo! project similar in nature to Google Answers, only funner and less authoritative. (ariels also points out that it's like a serious version of The Internet Oracle in some respects.)
Y!A is different from Google Answers in that it's more democratic: anyone can ask and anyone can answer. It's also more fun, for exactly one reason: it has points, much like E2's experience system.
When you sign up, you gain 100 points, making you a level 1 user. This is good, because until you're level 1 (1-249 points), you can't do anything. But once you're level one, you can ask up to five questions per day, rate others' answers (20 rates per day), vote on which answer is best (10 votes per day), comment on others answers (10 comments per day). You get a few points for each thing, with the exception of asking a question, which costs five points (which are reclaimed when you select the best answer).
As you gain points, you increase your level and get the ability to do more of each. You know, like on E2. Once you get to level five (5000+ points), you get unlimited questions, answers, and comments per day.
However, the system is much less effective than that of E2. When I post an answer, I get two points. If it's a violation of the TOS, it'll be deleted, but most things aren't. If someone asks a simple question, twenty people might post the same one-word answer and they'll each get their two points. Worse, ten people might post the correct answer and ten various incorrect answers and they'll all still each get two points. Worser, it's far from unheard of for an incorrect answer to be voted by the uninformed public as the 'Best Answer', getting the poster an extra ten points. There's no penalty for being wrong. Of course, it's still young. The Y!A team will hopefully continue working to improve these issues.
Okay, so the answers sometimes suck (though usually they're correct) and are often redundant. Similarly, you'll get dumb questions like 'What's your favourite colour?' Poll-like questions don't really seem like they belong, or perhaps should be in a 'Stupid poll category'.
What's it good for then?
For most of the questions, a simple Google query will give you the answer a lot faster and more easily than Y!A will. I've tried it for things that I can't easily find on Google and am hoping someone else will have more luck. This didn't work terribly well either, but can be worth a shot. Where Yahoo! Answers shines the most, though, is in questions that merit opinion essay answers and the like. Yahoo! likes to encourage this some by getting celebrities to ask questions such as 'What can we do to make poverty history?' (Bono) or 'How can the human race survive the next hundred years?' (Stephen Hawking). You'll get a lot of dumb answers to such things, but you'll also get thoughtful essays, and occasionally you may find a real gem.
You hate it, don't you?
Oh, I don't know. I don't love it, but it is somewhat addictive. If you don't mind wading through a lot of crap, it's nice. If you enjoy researching and answering questions, it's fun. But don't count on a highly intellectual population.
What I'd really like to do is create an account there and answer the poll-like questions, post redundant answers like everyone else, and consequently fly up to #1 user in a few weeks. I probably could do it, but it would also probably be immoral, especially since they only allow one account per person. I don't want it done under my real account name.
Update almost a year later
Yes, I hate it.
Okay, it's improved some technically. You can now vote up and down answers at any time, in a very Digg-like system. That's nice, except with a general population of trolls and idiots, it Just Doesn't Work. I was just browsing through Nancy Pelosi's question 'Congress is working on legislation to address global warming - what would you like to see included?' Hundreds of positively rated people declaring all sorts of pseudoscience, as well as open trolling. Honest questions are trollfests. If you ask an honest question about God in the religion section, atheists will post off-topic responses about how God is evil and religious nuts will post off-topic posts about how atheists are all going to hell. Of course, if you're a Y!A user, you'll not post an honest question, but instead an obvious troll posing as a question. Y!A is a trollfest, and little more, at least in some sections. If you're an idiot and want to trade stupid arguments with other idiots, Y!A is for you. If you want intelligent responses, you're out of luck.
The majority of people on Y!A are clueless and unhelpful, or trolls and unhelpful. And that's or, not xor. That occasional real gem may appear, but it will probably be voted way down for not being liberal/conservative/whatever enough. People are assholes, and thank you, Y!A for keeping them occupied on your servers.
Some fun
From avalyn: A Shockwave Flash animation of a 'typically' question: http://www.somethingawful.com/flash/shmorky/babby.swf
An actual question (qid=20080808091149AA3VGTk), though now deleted: http://feedproxy.google.com/~r/failblog/~3/MYXhLcERXtk/