Sure, here are some brief descriptions of the unique features and communities of each of the top 10 question and answer websites:
1. Quora: A platform that is popular for its diverse user base and high-quality answers from experts and professionals in various fields.
2. Stack Exchange: A network of Q&A communities covering a wide range of topics, with a reputation system that rewards helpful contributions.
3. Yahoo! Answers: A long-standing Q&A website that allows users to post questions and answers on various topics, with a voting system that determines the best answers.
4. Reddit: A social news and discussion website with numerous subreddits dedicated to different topics, where users can ask and answer questions.
5. Ask.fm: An anonymous Q&A social networking site that allows users to ask and answer questions from other users.
6. Answers.com: A question and answer site that provides answers to various topics, with a focus on factual and informative responses.
7. Super User: A Q&A site specifically for computer enthusiasts and power users, with a reputation system that rewards contributions and expertise.
8. Ask Me Help Desk: A Q&A site that covers a wide range of topics, with a focus on helping users solve practical problems.
9. Blurtit: A Q&A site that encourages discussion and debate, with a focus on user-generated content and community participation.
10. Answerbag: A Q&A site that covers a wide range of topics, with a voting system that determines the best answers and a community-driven approach to content creation.