BuiltWith - Find out the technology behind websites
HubSpot Free Email Marketing - Powerful drag and drop email marketing in the HubSpot CRM
Wappalyzer - Wappalyzer is a technology profilers and leads data provider. Create lists of websites and contacts that use certain technologies.
Email Marketing: A Beginner's Guide - Master email marketing with these 3 short ebooks from Drip.
What CMS - WhatCMS.org looks at a variety of factors within a webpage to determine what CMS a website is using.
Elevatr Email Marketing Automation - Fast and easy email marketing software