BBCode or Bulletin Board Code is a lightweight markup language used to format posts in many message boards. The available tags are usually indicated by square brackets ([ ]) surrounding a keyword, and they are parsed by the message board system before being translated into a markup language that web browsers understand—usually HTML or XHTML. BBCode was introduced in 1998 by the messageboard software Ultimate Bulletin Board (UBB) implemented in Perl. In 2000 BBCode was used in phpBB—an internet forum system written in PHP and also XMB forum. vBulletin also uses BBCode.