A free self-hosted solution is definitely competition. But many people will probably still think it is convenient to use a hosted service and pay for it. It's

A free self-hosted solution is definitely competition. But many people will probably still think it is convenient to use a hosted service and pay for it. It's the same with Gmail, salesforce, 37signals products and many other services. There are almost always free open-source alternatives, but not everybody wants to deal with installation, hosting and maintenance of those solutions.