UPDATE 2-Slide takes $50 mln in funding amid Facebook craze

(Adds interview comments, comparative financing data, byline)

By Eric Auchard

SAN FRANCISCO, Jan 18 (Reuters) - Social network software maker Slide Inc said on Friday it had closed a $50 million institutional financing round, marking the rising valuations of start-ups riding fast-growing Facebook's wave of popularity.

Slide made some of the hottest programs running on Facebook and News Corp's NWSa.N MySpace, including media-sharing applications Slide Shows, Top Friends, SuperPoke! and FunWall.

Max Levchin, its Ukranian-born and Chicago-raised founder, declined to name the investors. But sources close to the deal said they were Fidelity Investments and T Rowe Price (TROW.O).

The round is nearly 10 times the size of the median round of $5.18 million for Web 2.0 firms in the first half of 2007, according to Dow Jones investment tracking unit VentureOne.

This follows the roughly $500 million recently raised by Facebook from Microsoft Corp (MSFT.O) and Hong Kong billionaire Li Ka-shing, giving it an implied $15 billion valuation.

Slide, incorporated in 2005, was originally self-funded by Levchin, 32, who co-founded online payments company PayPal a decade ago. He later took funding from Peter Thiel, the other founder of PayPal, which eBay Inc (EBAY.O) bought in 2002.

Subsequent funding for San Francisco-based Slide was provided by leading Silicon Valley venture capitalists Mayfield Fund, former Nokia (NOK1V.HE) venture arm BlueRun Ventures, Khosla Ventures and Founders Fund, Thiel's venture fund.