Realty Pilot - Realty Pilot is a suite of paperless real estate software.
Wappalyzer - Wappalyzer is a technology profilers and leads data provider. Create lists of websites and contacts that use certain technologies.
Top Producer - Real estate crm software.
BuiltWith - Find out the technology behind websites
Bubblehunt - Discover products based on recommendations from influencers
What CMS - WhatCMS.org looks at a variety of factors within a webpage to determine what CMS a website is using.