CubeTree, a freemium enterprise collaboration suite built on a social networking platform, announced on Wednesday that it raised $8 million in Series B financing.  InterWest Partners led the round, while Trinity Ventures also participated in the round.  To date, the company has raised about $12 million in funding InterWest Partners, Trinity Ventures and Mitch Kapor.

In short, the Redwood City, Ca.-based startup is the developer of a social networking platform for enterprises.  So pretty much all the features you find on Facebook and Twitter, like friends, micro-blogging, sharing information, status updates, etc, are all available within CubeTree.  The difference is the social network you build for your enterprise with CubeTree is solely for your enterprise.  

Launched in May of 2009, the product is being offered for free but limited to certain features.  Pro accounts cost $3/user/month and Enterprise accounts, which offer custom branding cost $5/user/month.  CubeTree is delivered as a software service.

CEO and co-founder of CubeTree, Carlin Wiegner stated, "CubeTree is seeing strong and increasing market demand for enterprise social software suites.  Enterprise social software is an extremely fast-moving space and this new investment round will allow us to maintain our aggressive speed of product innovation, while accelerating the growth of the company."

The company competes with other social networking platforms like Socialtext and PBWorks.

CubeTree said it would use the funding to continue investing in product and market development.