Hi Georg,
A point well made - a lot of the 'extra stuff' certainly deserves a home on the PI server.
However, for the sake of discussion, let's consider Harry's Video Tutorials. He is, quite rightly, proud of his achievement. So he puts them on his own website, and we all flock to them, downloading like mad (perhaps pushing his own private bandwidth allocation to the limits permitted by his ISP). And we wait for his next one.
But, in the meantime, in the new PI server setup, Juan graciously asks if Harry would like the videos to be hosted on the PI server. Harry is happy and onto the server they go.
Now, what does Harry do? If he doesn't tear down his own distribution page, then we end up with a parallel setup, with the highly likely possibility that the two sites will eventually NOT contain the same information. So, Juan would have to permit Harry to 'control' the new server location, and web-page front end, so that all changes, updates, corrections, etc. can be made by Harry himself.
Problems still exist regarding 'ownership' and 'intellectual property' - but I think that they could be solved by a simple agreement between author and server host.
But, what happens if Harry 'gets bored' and no longer updates the pages, or if Juan needs to do a major website revamp. What happens if someone else want to add a video tutorial to the web page, but has no idea, or inclination, to do the detailed work (other than create the video itself)? Someone then has to take the video and 'paste' it in to the website in an appropriate manner (the video obviously having been vetted by this time, and deemed suitable for inclusion).
To my mind, the devolvement of control of the server will have to be passed to a wider group, still under Juan's overall supervision of course, with different team members having responsibilities for different areas.
It will be an interesting task !