Viacom subsidiary MTV Networks acquired the rest of software company Social Project, which runs Flux, a platform for social networks. Flux links together sites and gives them social features like messaging and video sharing. MTV already owned a large stake in the company and had 35 sites on the platform. MTV plans to turn Flux into an ad network because "the Web is fragmented,” says Mika Salmi, MTV's president of global digital media. “People are attracted to niches. We have a history in the cable business of going after niches.” True enough: Online, MTV has a history of turning what should be successful, mainstream ventures into mere niches.