Tsung - Tsung is an open-source multi-protocol distributed load testing tool.
Foursquare - Foursquare is all about helping you find new ways to explore your city.
gatling - A high performance web server. Small! (125k static Linux-x86 binary with HTTP, FTP and SMB support).
Tripadvisor - The Tripadvisor mobile app is available for the Android and iOS platforms. It can be used to create reviews of hotels, restaurants, and to chat with other travelers on Tripadvisor forums.
locust - An open source load testing tool written in Python.
Yellow Pages - YP.com local search connects you with over 19 million local businesses.