Bulk Email Verifier - Clean up your large mailing lists before you use them. Clean list increases your reputation in MailChimp, AWeber, or Campayn.
BuiltWith - Find out the technology behind websites
Email Verifier - Email verifier app lets you verify email.
Wappalyzer - Wappalyzer is a technology profilers and leads data provider. Create lists of websites and contacts that use certain technologies.
Email List Verify - The Fastest Way to Improve Email List Deliverability and ROI
What CMS - WhatCMS.org looks at a variety of factors within a webpage to determine what CMS a website is using.