Actually I think that GPL almost goes as far to encourage this hosting model. If you want to incorporate non open source code or libraries then you actually CAN

Actually I think that GPL almost goes as far to encourage this hosting model. If you want to incorporate non open source code or libraries then you actually CAN'T release that code to the world. The only way to offer people that functionality is to host it.. and nobody else can offer a non-hosted solution. I can see a lot of startups following this model with GPL in particular.