Aardvark Alternatives

Quora.com is a question/answer service allowing users to pose questions that other users can answer, each question and answer can have comments, each users can write one individual answer and there can be a summary answer. Each user can choose a description explaining their area of expertise or questions and answers can be anonymous.
Questions and answers are searchable.

Yahoo! Answers is a way to find and share information.

Stack Exchange is a fast-growing network of 84 [and counting] question and answer sites on diverse topics from software programming to cooking to photography and gaming. We are an expert knowledge exchange: a place where physics researchers can ask each other about quantum entanglement, computer programmers can ask about JavaScript date formats, and photographers can share knowledge about taking great pictures in the snow.

Super User, part of Small Stack Exchange iconStack Exchange , is a Q&A site for computer enthusiasts that’s free. Free to ask questions, free to answer questions, free to read, free to index, built with plain old HTML, no fake rot13 text on the home page, no scammy google-cloaking tactics, no salespeople, no JavaScript windows dropping down in front of the answer asking for $12.95 to go away. You can register if you want to collect karma and win valuable flair that will
appear next to your name, but otherwise, it’s just free. And fast. Very, very fast.

Server Fault is a Q&A site for system administrators and IT professionals that’s free.

Question and answer service based on user profiles and a user score.

Experts123 is a Question and Answer Encyclopedia that provides answers from an Expert community.

askalo was a social networking and user-generated local question-and-answer (Q&A) site. Askalo users could ask questions about any local topic and share answers tailored to their individual needs.

Stack Overflow is the largest, most trusted online community for developers to learn, share.