Microsoft sued Acacia Research Corp. today, accusing the company of breaking a contract "to license various smartphone and mobile computing technologies to Microsoft," Reuters reported.

The suit was filed in US District Court in New York, but it's currently under seal, which means that details are thin. The Microsoft accusations come in response to recent suits Acacia subsidiaries filed against Microsoft that allege infringement of more than a dozen patents. Acacia filed these lawsuits despite the fact that "in 2010, Microsoft agreed to pay an Acacia subsidiary to license a portfolio of patents related to smartphones and tablets ultimately owned by Tokyo-based Web browser firm Access Co.," Reuters wrote.

"Acacia's lawsuits are the worst kind of abusive litigation behavior, attempting to extract payment based on litigation tactics and not the value of its patents," Microsoft Deputy General Counsel David Howard told Reuters.

One of the lawsuits against Microsoft was filed in October by Intercarrier Communications, which is apparently an Acacia subsidiary. Intercarrier sued Microsoft and its Skype and GroupMe divisions in US District Court in Delaware; it alleged infringement of a patent covering a "phone number only messaging experience" as part of an SMS deployment.

Innovative Display Technologies, another apparent Acacia subsidiary, sued Microsoft in US District Court in Eastern Texas, alleging infringement of patents covering "Light Emitting Panel Assemblies."

Acacia has been making the rounds for years, buying patents from other companies and then getting cash through licensing agreements or suing companies that refuse to pay for licenses. For example, Acacia sued Oracle, Corel, Kodak, Nuance, Borland, Novell, and others in 2007, claiming infringement of patent on "products sold or distributed on CDs or DVDs that include a link to retrieve additional data via the Internet."

Acacia in October 2010 licensed 74 smartphone patents to Microsoft, including technology developed by Palm. "Some of the patents included in this agreement are involved in a lawsuit filed by Acacia in March [2010]," we wrote at the time. "The company is suing Apple, RIM, Samsung, and Motorola—though not Microsoft—for infringement of patents covering areas such as e-mail synchronization and the provision of telephony features in a personal computer."

Microsoft defeated an Acacia subsidiary in one patent suit in late 2007 when a jury declared a patent on speeding up PC boot time invalid.

Acacia's stock dropped nearly four percent today.