Stack Overflow - Community-based Q&A part of the Stack Exchange platform.
StackAdapt - Native advertising demand side platform.
The Answer Bank - The Answer Bank is the UK’s leading question-and-answer site.
Zemanta - Zemanta is an online content and links suggesting platform that provides a plugin to the bloggers, publishers and other types of content creators.
Askalot - Askalot is a next generation CQA (Community Question and Answer) system.
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.