Social media giant Facebook has filed suit against adult dating site Shagbook. The case: that Facebook's reputation would be damaged "by the issuance of a registration" of its name to Shagbook.

Facebook filed the claim with the United States Patent and Trademark Office in May. Shagbook has now filed its own opposition and counterclaims.

The Facebook suit claims that the small dating site has too similar a name to the world's largest social network. A spokesman for the dating site responded in a report in Mashable that the owner of the site got the name from his own term for his little black book.

"He was amused with the word 'shag', and picked up the name Shagbook.com, all perfectly innocently," he said.

Shagbook has denied Facebook's allegations that it copied the company's name as Facebook is a generic term. The much smaller dating site, established back in 2006 also states that the multi-billion company Facebook is using bullying tactics against its competitors. It also challenges the validity of Facebook's trademark, claiming that it should never have been granted in the first place.

Shagbook, which was established as a casual dating site in 2006, has hit back with a counter-suit, stating the much bigger Facebook is employing bullying tactics against its competitors, and claimed the social network should never have been issued the trademark in the first place.

Facebook alleges that Shagbook is in violation of Facebook's trademark because the dating site's name is similar in "appearance, sound meaning, and commercial impression." The dating site adopted the name with "the intent to call to mind and create a likelihood of confusion ... and/or trade off the fame of Facebook."

Facebook has launched previous trademark claims against other companies who used the word "face" or "book" in their website names. Teachbook and Facebbookofsex.com have been targeted by social network giant for trademark infringement.

Shagbook and Facebook attorneys have spoken but negotiations haven't started according to the SNRG representative.

"SNRG plans to vigorously defend the Shagbook mark," said the spokesman.

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