On April 30, 2009, Twitter adjusted its web interface, adding a search bar and a sidebar of "trending topics" — the most common phrases appearing in messages. Biz Stone explains that all messages are instantly indexed and that "with this newly launched feature, Twitter has become something unexpectedly important – a discovery engine for finding out what is happening right now."
In March 2012, Twitter became available in Arabic, Farsi, Hebrew and Urdu, the first right-to-left language versions of the site. About 13,000 volunteers helped with translating the menu options. In August 2012, beta support for Basque, Czech and Greek was added, making the site available in 33 different languages.