The Scrabulous application remains available in India, where its developers live and where Mattel has filed a lawsuit claiming violations of intellectual property. Facebook isn't blocking Scrabulous there for now, considering the question of ownership still a matter for Indian courts to resolve.
In deciding to block Scrabulous on Friday, Facebook risked antagonizing a community of software developers it has been trying to nurture and promote. But had it done nothing, it could have faced liability for copyright and trademark infringement.
The company initially skirted that quandary after Rajat and Jayant Agarwalla, the brothers in Calcutta who created Scrabulous, agreed to withdraw the program in the United States and Canada following a legal threat from Scrabble's North American owner, Hasbro Inc.
Facebook had hoped for a similar resolution when Mattel, owner of Scrabble's rights elsewhere, sent a similar notice, but the Agarwalla brothers refused.
In a statement, Jayant Agarwalla said he found Facebook's action "astonishing" given the site's "claims to be a fair and neutral party."
The bulk of his criticism was directed at Mattel, however.
"It surprises us that Mattel chose to direct Facebook to take down Scrabulous without waiting for the (Indian court's) decision," Agarwalla said. "Mattel's action speaks volumes about their business practices and respect for the judiciary."
Mattel representatives did not respond to e-mail and phone messages Monday.
Both Hasbro and Mattel have been trying to promote an authorized version of Scrabble for Facebook - made by Electronic Arts Inc. in the United States and Canada and by RealNetworks Inc. elsewhere.
The Agarwallas, meanwhile, have released an alternative Scrabble-like word game called Wordscraper, which was not affected by Facebook's latest action. They are hoping that with new rules and circular tiles instead of square ones, Wordscraper can withstand legal challenges.