Everyone seems to love the online game — everyone, that is, except the companies that own the rights to Scrabble: Hasbro, which sells it in North America, and Mattel, which markets it everywhere else.

In January, they denounced Scrabulous as piracy and threatened legal action against its creators, two brothers in Calcutta named Rajat and Jayant Agarwalla who run a software development company. Both Hasbro and Mattel said they were hoping for a solution that would not force them to shut down the game.

Jayant Agarwalla, 21, said they did not create Scrabulous to make money, even though they now collect about $25,000 a month from online advertising. They just wanted to play Scrabble on their computers, and their favourite (unauthorised) site had started charging, he said.

“Our family has been playing the game for 50 years now,” he said, and received a set when the game first came out in India. His mother encouraged him and his 26-year-old brother, Rajat, to play as a learning tool, often with a dictionary by the board.

Scrabulous, which most users play on the Facebook social-networking site, has a board that looks just like Scrabble, and the same number of letter tiles with the same point values. Players can send invitations to others on Facebook or search for strangers to play with by posting messages. There is no time limit for moves or games. Scrabulous keeps track of player statistics, and it does not allow fake words. It cannot, however, prevent players from cheating. One method is an unaffiliated online “helper” program, which generates a list of possible words based on the letters a user has.

Two game companies, RealNetworks of Seattle and Electronic Arts of Redwood City, Calif., say they have signed deals with Hasbro to create online versions of the company’s games.

The threat of legal action has not gained the companies many admirers. Many Scrabulous fans, some of whom say they bought the board game for the first time after playing the online version on Facebook, call their approach heavy-handed and out of touch.

Morgan, who is the host of a Facebook group called “Help, I’m a Scrabulous Addict,” attributes the game’s popularity to “all these people who are bored at work in their office,” and added that the game keeps him in regular contact with his mother.

The legal questions concerning Scrabulous are complicated by the interests of the companies that own the rights to Scrabble.

Harold Zeitz, senior vice president for games at RealNetworks, said Friday that he was working closely with the Agarwalla brothers to bring the official Scrabble game to Facebook users.

Scrabble began as Lexico in 1931, the creation of an out-of-work architect, Alfred Mosher Butts. He determined the frequency of each letter in the game and its value by reviewing the front page of The New York Times.