Slide was founded by PayPal co-founder Max Levchin.
"As the Slide team joins Google, we'll be investing even more to make Google services socially aware and expand these capabilities for our users across the Web," Google Engineering Director David Glazer wrote in a company blog on Friday.
Google has struggled to find the right touch in creating the types of social networking services that have become increasingly popular online activities for consumers.
On Wednesday, Google announced it would pull the plug on Google Wave, a high-profile social networking product that launched last year.
Media reports have said Google is developing a new social networking product dubbed Google ME in a bid to challenge Facebook, which has more than 500 million users worldwide.
Slide has roughly 120 employees. Almost all are expected to join Google as part of the acquisition.
The purchase of Slide is the latest of a string of recent acquisitions by Google, including recently announced plans to buy online travel company ITA Software for $700 million.
Google, based in Mountain View, California, has bought 22 companies in the first six months of 2010, according to the company's most recent quarterly filing with the SEC.
Slide was founded by Levchin in 2005 and had raised roughly $75 million in venture funding from firms including the Mayfield Fund and Khosla Ventures.
Google's Slide acquisition was first reported by the technology blog TechCrunch earlier this week.
Source: (wateen.net)