Hunter TechLookup - Create lists of websites by technology for free
Landing Pages in MailChimp - Easy to build, custom landing pages for free
xZeitgeist - The most popular tweets categorized and ranked, every day
Viral Loops for Startups - Virality for startups made easy 💪
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!
Carrd - Simple, responsive one-page site creator.