Fred Wilson continues to argue in favour of free:
I understand the frustration of certain folks about the commercialization of Twitter, Facebook, Tumblr, and a host of other services. I understand the frustration over the increasing lock down of the APIs and the control these platforms are exercising on their ecosystems. I would encourage folks to compete with them to keep the web, the mobile web, and the Internet free and open. But I would not encourage those same folks to build paid services. I think their goals will be undermined by that choice.