Two official versions of Scrabble are available on Facebook, one for residents of the U.S. and Canada and the other for residents of other countries. A third Scrabble-like game, Lexulous, is also available. (Lexulous was known as Scrabulous until lawsuits were filed against the creators by both Hasbro and Mattel.)
Free registration is required to join Facebook.
Games.com, run by AOL Games, offers players five versions of Scrabble, including the classic board game.
Other versions include Scrabble Blast (play online or download), Scrabble Cubes (play online), Scrabble Journey (download only), and Scrabble Rack Attack (play online or download).
Free registration is required to join Games.com.
In addition to being available at Facebook, Lexulous can be played at Lexulous.com.
Free registration is required to join Lexulous.com.
Pogo.com, run by Electronic Arts, is an official place to play Scrabble. Two versions are available: classic Scrabble (for two to four players) and Scrabble Blast (a solo game fairly described as Scrabble meets Boggle).
Free registration is required to join Pogo.com.
Scrabb.ly, an independent crossword game, is a massively multiplayer online game. Once you play your first word, you keep building on your own work. Anytime you need to swap tiles, you lose a life (you only have a total of three). When your last life ends, your score is calculated.
Yahoo Games offers a game called Literati, a crossword game with similarities to Scrabble.
Free registration is required to join Yahoo Games.