Gartner recently had a conference on Open source, Just some excerpts from the blogsphere on the same.

Ray Valdes cited a number of examples in his presentation such as:

• Sabre Holdings reduced their TCO by over 40% by implementing their open source fare search system (ATSE) using Red Hat Enterprise Linux, MySQL and Tomcat (with a smattering of JBoss). The system runs on more than 45 quad CPU linux boxes and handles 20 million fare records, 1.5 million scheduled departures and 3 billion price combinations! The overall system scales to handle 300 transactions per second
• .
• TheFaceBook has more than 8 million unique visitors delivering 5.5 billion page views per month, making it the tenth most visited site in the US. They get 93% repeat visitors per month and 70% of their users visit every day. The amazing thing is the system was written in 10 days by a college kid (now their CEO) during final exams! What does the system run on? LAMP stack, using MySQL, naturally.
• Cendant has a travel system that handles more than 700 pricing requests per second all built on a Red Hat open source stack
• Morgan Stanley has implemented more than 1000 Linux Servers for various applications

Valdes also gave examples of "Global class" web sites such as Amazon, Schwab, expedia, as well as some unconventional (by IT standards) sites like MySpace, Zanga, LiveJournal that are all built on open source. MySQL came out very well represented in these scale-out applications.

Source: TheOpenForcePrashanth RaiTag(s):Open+Source