Joost, the P2P TV venture from European hit makers, Niklas Zennstrom and Janus Friis has signed on Viacom as a content partner, a move that will bring content from various Viacom properties – MTV, Comedy Central and Showtime – to the P2P service, reports the Wall Street Journal.

The deal, of course was helped by the fact that a trio of former MTV executives are in pretty senior positions at Joost aka The Venice Project. David Clark (EVP, Global Advertising and GM North America), Yvette Alberdingkthijm (EVP, Content Strategy & Acquisition) and Henrik Werdelin (Chief Creative Officer) form the trio that are charged with bringing content partners to the Joost platform. Of course they started with the company they know best – Viacom.

The terms of the deal are not revealed but WSJ speculates that Viacom typically gets two-thirds of the advertising revenues that come as a result of their videos. For Joost this is a big coup, and will result in big media companies taking them more seriously.

One has to temper the excitement around this development by pointing out that for Joost, signing up content partners is going to be a long drawn out process. Sort of like putting pants, one leg at a time. Joost needs these kind of deals more desperately than content owners and might have to sacrifice a larger share of revenues in order to sign up big media.

The deal is also a sign that if Viacom treads carefully, it could become one of the biggest beneficiaries of the online video boom. As Robert Young argues in his column today, “Opening up their vaults to the masses, for the first time in their history, is a watershed event that should not be underestimated.” You can say the same about other large media companies, but then we have seen in the past – most incumbents move too slowly and only have to blame themselves for missed opportunities.