Question2Answer - A Q&A site helps an online community to share knowledge.
Site Rank Data - View historical rank information of websites via time series charts.
Stack Overflow - Community-based Q&A part of the Stack Exchange platform.
HypeStat - HypeStat is free statistics and analytics service, where you can find information about every website.
The Answer Bank - The Answer Bank is the UK’s leading question-and-answer site.
Q-Stats - Get free marketing insights for every question on Quora.