Mainstream Holdings, an internet holding company led by former ETrade CEO Christos Cotsakos has raised $29.6 million to build out its social net MOLI. The funding comes from a group of individuals including Home Depot founders Bernard Marcus and Kenneth G. Langone and Steven Holzman of Vantis Capital Management. MOLI is the core holding of Mainstream Holdings, which was previously funded with $20 million from Cotsakos and $6 million from outsiders, bring its total to $55.6 million. The core social networking service is pitched towards users that want to maintain multiple identities, depending who is looking. It also offers networking based around specific groups, along with a platforms for blogging and video. Mainstream Holdings’ other assets include CoVibe, which owns the underlying technology behind Moli, Tertiary Productions, which does original HD content and MOLI Kids. The company says it will be using the funding to enhance MOLI, which officially launches today. It feels like a lot of money for an un-proven site, although it may have ambitions to build out its other technologies and services as well, beyond this one site. Release.