ConvertAll - A comprehensive unit conversion program.

BuiltWith - Find out the technology behind websites

Tweetbot - Sync your timeline across your iPhone, iPad, and Mac. Mute tweets by user, hashtag, tweet source, or keywords (including regex). 3rd Party support for image, video, read later, and timeline sync services.

Wappalyzer - Wappalyzer is a technology profilers and leads data provider. Create lists of websites and contacts that use certain technologies.

multiConvert - multiConvert is a simple to use small sized unit converter for converting any unit into another one and getting the real time result on the main window of this program.

What CMS - WhatCMS.org looks at a variety of factors within a webpage to determine what CMS a website is using.