BuiltWith - Find out the technology behind websites

Stackshare - StackShare is a comprehensive website that gives its users the chance to organize and share their technology stack with the rest of the community.

Lead Forensics - B2B website analytics and lead generation.

Techmap.io - Techmap is a workplace search engine to find companies using technologies (e.g., Rails, PHP, Java, etc.) that are used internally. Finally, a "Google for Workplaces" that helps people find a place to work with technologies they love!

FindThatLead Prospector - Feed your sales team with daily leads.

Setalist - The easiest way to make awesome lists for the internet