The way in which it’s done so is a bit unusual, but the venture capital firm founded by Marc Andreessen and Ben Horowitz has thrown its weight behind Twitter.  A report’s indicated Andreessen Horowitz spent something like $80 million to buy into the company.

Kara Swisher wrote this afternoon, "Andreessen Horowitz has invested more than $80 million in Twitter via purchasing stock in secondary markets."

She then continued, "The move is an interesting one, since Andreessen Horowitz was not part of the recent $200 million round on venture funding at the San Francisco microblogging company, led by Kleiner Perkins and which valued it at $3.75 billion."

Perhaps this approach saved the organization some extra paperwork.  Or maybe someone’s check just didn’t arrive in time.  There aren’t a whole lot of other theories at the moment.

Anyway, Andreessen Horowitz had already invested in Digg, Facebook, Foursquare, Groupon, RockMelt, Skype, and Zynga, so the move fits into an established (and impressive) pattern of sorts.

Andreessen Horowitz did confirm its investment in Twitter, by the way, although neither party’s issued an official statement at this time.