WiseStamp - WiseStamp allows you to easily create and implement slick and unique email signatures for your business.
BuiltWith - Find out the technology behind websites
NEWOLDSTAMP - Email signature generator
Wappalyzer - Wappalyzer is a technology profilers and leads data provider. Create lists of websites and contacts that use certain technologies.
Sigstr - Email signature marketing
What CMS - WhatCMS.org looks at a variety of factors within a webpage to determine what CMS a website is using.