Quora - Quora is a place to gain and share knowledge. It's a platform to ask questions and connect with people who contribute unique insights and quality answers.

Stack Overflow - Community-based Q&A part of the Stack Exchange platform.

Tumblr - A feature rich and free blog hosting platform offering professional and fully customizable templates, bookmarklets, photos, mobile apps, and social network integration.

The Answer Bank - The Answer Bank is the UK’s leading question-and-answer site.

Reddit - Reddit gives you the best of the internet in one place. Get a constantly updating feed of breaking news, fun stories, pics, memes, and videos just for you.

Blurtit - Blurtit is a Q&A website. You can ask a question or answer on any question.