1. Yahoo Answers – Yahoo Answers is one of the most popular online forum where users can ask any kind of question. Yahoo Answers allows users to ask questions and give answers for free. Thousands of new internet users ask here about their problems. Community members help users by providing useful answers for free. Although you should not totally rely on their answers because some of those answer only for getting website traffic or promoting their products. Yahoo launched this service in 2005 and now it is one of the most visited online communities where people discuss about their favorite topics.
2. Digital Point Forums – Digital Point Forums is one of the most visited online discussion forums where millions of internet users ask questions and share knowledge per month. You can ask or answer here on these topics- search engines, online marketing, blogging, designing and multimedia, internet tools and advertising, computer and technology, business , Jobs etc.
3. WarriorForum – One of the most useful online discussion forums for bloggers and online marketers. This forum helps users to become successful & popular on the web by providing helpful content. Here you can find thousands of useful answers related to your queries. One of the oldest internet marketing forum that was started in 1997.
4. Google Product Forums – If you have any kind of question related Google products, Google product forums can help you to find your solution. You can find here all kinds of topics which are related to Google such as Google Adsense, Search engine, web master tool, android market, Google translate etc.
5. Mylot – Mylot is a popular online community where users discuss about their favorite topics such as technology, movies, music, online business, blogging, advertising, marketing etc. If you have knowledge, you can also make money by answering people’s question. Mylot also offers short online jobs where users can make extra money online.
6. Webhostingtalk – If you are a blogger or website owner, this forum could be the perfect option for you because here you can talk only about webmaster topics such as blogging, hosting reviews, hosting related problems etc.
7. Stackoverflow – Great question answer website that helps internet users to get help online by asking question to experts. You can ask your question here, community members will answer your question. Users can find useful content on their favorite topics. Stackoverflow was created in 2008 and now it has become one of the most popular question answer websites on the internet.
8. Answers – Answer is a great place to get help by asking question. Answer.com is one of the most visited Q & A website where you can find answers of your questions.
9. Linkedin Answer – Similar to Yahoo Answer. Users can discuss here on their favorite topics. If you have any kind of question or problem you can find here answer of your question. This service was started by linkedin in 2007.
10. Webanswers – One of the best place to get help online. If you are looking for any kind of information on the web, you can try webanswers. Webanswers also allows users making money by sharing knowledge. If you have Google Adsense account, you can also make money by answering people. This site shares adsense revenue to users.
Hope this list will help you to ask your question. I have missed listing many popular forums, you can find those by using Google Search.