Hasbro, the maker of popular word game Scrabble, filed a lawsuit in U.S. District Court in the Southern District of New York on Thursday against Scrabulous, a similar online application. In its complaint, Hasbro says Scrabulous manufacturer, RJ Softwares, has committed copyright infringement and engaged in unfair competitive practices.

Scrabulous has more than 500,000 daily active users on Facebook, a popular social networking site. 

Hasbro has formally notified Facebook of the problem and has asked for the application to be taken down. Under the Digital Millennium  Copyright Act, Facebook will not be liable for any alleged copyright infringement under a safe harbor provision. However, Facebook must respond to the notification or it will lose its immunity.

Source: http://www.chicagotribune.com/business/technology/chi-fri-hasbro-scrabulousjul25,0,7068069.story