Surfingbird.ru, the first collaborative content discovery service on the Russian-language Internet, raised $2.5 million last month from Russian and French business angels. The deal brought the startup’s valuation to just under $2.5 million, a source close to the deal told East-West Digital News.

Founded last year, SurfingBird was funded at seed stage by two Western business angels, one based in Moscow, the other in Barcelona. The service was launched this spring with a distinctive ‘share’ button spreading among Russian websites, including some popular sites like RuTube.ru, the top Russian video hosting service.

The founders told EWDN that the service is and will remain free, but the potential for advertising is strong. “Our system will meet the needs of advertisers seeking to launch highly targeted campaigns based on both declared and behavioral data.”

But a competitor, Netflip.ru, appeared just weeks after Surfingbird, filling a market segment that was completely empty six months before.

Both sites are inspired by US site StumbleUpon.com, which has grown into a major traffic provider for blogs and sites and which recently raised $17 million.