Facebook has filed a suit against adult dating site Shagbook in a trademark tussle that will be closely watched from bedrooms and boardrooms across the United States.
The world's largest social networking site says allowing Shagbook to register its name as an official brand would "damage" its trademark, according to Mashable.
Shagbook has fired back its own counterclaims in defense of its "book" addendum, saying Mark Zuckerberg's social networking giant doesn't have a monopoly on the word.
Shagbook's representatives, SNRG Ventures, say the upstart adult dating site's American owner was living in the United Kingdom when he started referring to his "little black book as his little ‘Shagbook’."
"He was amused with the word ‘shag,’ and picked up the name Shagbook.com, all perfectly innocently," a representative for SNRG Ventures told Mashable.
"SNRG plans to vigorously defend the Shagbook mark," he said.
In the filing, Shagbook says it "denies the allegation that Facebook is highly distinctive as it is a generic term."
Facebook argues that Shagbook is unlawfully similar in "appearance, sound meaning, and commercial impression" to its own trademark, and was created with intent to confuse customers.
The multi-billion-dollar internet giant filed its claim with the United States Patent and Trademark Office three months ago.
Facebook has previously challenged Teachbook and FacebbookOfSex.com on similar trademark grounds, according to Silicon Republic website.