BuiltWith - Find out the technology behind websites
madkudu - We’re building a better knowledge base
Wappalyzer - Wappalyzer is a technology profilers and leads data provider. Create lists of websites and contacts that use certain technologies.
ManyContacts - Create and install a Contact Form in minutes. Easily convert your website visitors into qualified leads. ManyContacts provides a FREE online contact form for conversion optimization.
What CMS - WhatCMS.org looks at a variety of factors within a webpage to determine what CMS a website is using.
Sparklane - Sparklane offers predictive lead scoring solutions.