They could easily be profitable immediately if they put big ads on the homepage. But that would hurt the experience. As long as they don't need the money, they

They could easily be profitable immediately if they put big ads on the homepage. But that would hurt the experience. As long as they don't need the money, they want to keep the user experience as good as possible. The hope is that they will develop a less intrusive, more targeted form of advertising that is still effective.