Words With Friends is a multi-player word-oriented mobile game developed by Zynga With Friends (formerly Newtoy, Inc.). It challenges players to take turns building words crossword puzzle style with one or more friends, or by being matched with random opponents. Its rules and points system is based on that of the popular board game, Scrabble. Up to 20 games can be played simultaneously using push notifications to alert players when it is their turn. Released July 2009 and published by Zynga, Words with Friends is available for cross-platform play on devices running the operating systems Android and iOS (iPad, iPhone, iPod Touch). In addition, there is a chat feature built in the game that allows you to chat with your opponent. The Words with Friends is one of the top ranking games in the iOS application store, available as both a free ad support and an ad-less paid version.
Source: Wikipedia, "Words With Friends", available under the CC-BY-SA License.