Facebook: 300M active users, 30,000 servers, 230 specialists
In April 2008, the company had about 10,000 servers . Since then, the company’s growth has been + 20k in 18 months , if you count in purely server terms, and Facebook has taken a legal place among the Internet super-buffalo .
Open source software is installed on the servers, Memcache and Hadoop are actively used.