BuiltWith - Find out the technology behind websites

Parse.ly Analytics - Analytics for understanding audience attention

Wappalyzer - Wappalyzer is a technology profilers and leads data provider. Create lists of websites and contacts that use certain technologies.

GoSquared People Analytics - One place to understand your users

WhatRuns - Extension that helps you identify technologies used on any website at the click of a button.

Known Pro - The best way to reach your audience from a single platform