The portal is part of a network of 30 sites run by Intermix that attracts more than 27m unique monthly users and, according to News Corp, served 8% of all ads on the internet in June. The acquisition will nearly double News Corp's unique monthly users to 45m.
Intermix has been operating for six years and last year made a profit of $4.5m (£2.59m) on turnover of $79m (£45.4m).
MySpace.com is similar to Yahoo, offering a community of users email, blogs, chatrooms, music downloads, classified listings, photo galleries, and personal web profiles.
News Corp has been widely expected to expand its online interests since February, when Murdoch gathered his top executives in New York to discuss how to react to the internet's rising popularity.
One of the results of that meeting was the formation last Friday of a business unit, Fox Interactive Media, into which Intermix will be slotted.
Murdoch, chairman and CEO of News Corp, believes that this online audience overlaps with the audience for his Fox news and entertainment stable of TV channels and websites, which include foxsports.com, foxnews.com and fox.com.
He said: "Intermix's brands are some of the web's hottest properties and resonate with the same audiences that are most attracted to Fox's news, sports and entertainment offerings.
"We see a great opportunity to combine the popularity of Intermix's sites, particularly MySpace, with our existing online assets to provide a richer experience for today's internet users."
Intermix also has a marketing division called Alena, which develops online marketing strategies for selected products, especially nutrition and health products.
If you have an opinion on this or any other issue raised on Brand Republic, join the debate in the Forum.
This article was first published on brandrepublic.com