Facebook was founded in 2004 by Harvard students to connect university students. It expanded to any university and then worldwide. Technologies behind Facebook include Memcached for caching, HipHop/HHVM for compiling PHP to C++, Haystack for photo storage, BigPipe for page loading, Cassandra for messaging search, Scribe for logging, Hadoop/Hive for data analysis, Thrift for language integration, Varnish for caching photos and profiles, and React for the frontend JavaScript library.