News Corp paid $580m (£361m) for MySpace in 2005, but users and advertisers left the site for rival social sites like Facebook and Twitter.
The sale terms were not disclosed, but there were unconfirmed reports that price paid was as low as $35m.
Specific Media said: “We look forward to combining our platforms to drive the next generation of digital innovation.”
Specific Media was founded in 1999 by three brothers – Tim, Chris and Russell Vanderhook – and is based in Irvine, California.
MySpace was a leading social networking site when it was bought by Rupert Murdoch’s News Corp.
But the business was eclipsed by rivals, and despite attempts to revive MySpace’s fortunes the site has been a financial millstone.
The Reuters news agency cited a News Corp-owned blogging site as reporting that MySpace was sold for $35m.
News Corp’s chief operating officer Chase Carey said in November that the losses at MySpace were “unsustainable”.
Although News Corp does not publish specific results for MySpace in its accounts, the “other” segment, which includes the social network, reported a second quarter operating loss of $156m – $31m worse than a year earlier.
According to tracking firm comScore, MySpace had 21.8 million unique monthly US visitors in August 2005 compared with Facebook’s 8.3 million.
In May, Facebook’s monthly US visitors had risen to 157.2 compared with MySpace’s 34.9 million, comScore said. Facebook has nearly 700 million members worldwide.