Facebook has been asked by makers of the classic word game Scrabble to remove the online version of "Scrabulous" from the popular social networking site.

In North America, the rights to the game are owned by Hasbro Inc., the company which also owns Monopoly, Trivial Pursuit, Risk, Clue, and Magic: The Gathering. The rights to the game in the rest of the world are covered by Mattel Inc., the world's biggest toy company, who sent the demand to Facebook.

Scrabulous was created by two entrepreneurs from Kolkata, India and launched in July 2006. Rajat and Jayant Agarwalla were ardent fans of the board game, and created Scrabulous after not finding an online version to their liking.

Scrabulous even includes a disclaimer on its Web site that it is in no way connected to Hasbro or Mattel, but the owners hope it encourages people to purchase the official board game.

According to Facebook, 600,563 users -- 26% of Facebook's daily active membership -- use the Scrabulous application daily.