Just saw Knight and Tim’s posts.

To Tim: If you register for one server it transfers all data to each other server (main advantage of one Database)

To Knight: Yes. This is my „big mountain“. As for forums, no, no CMS’s will be hosted, just the normal site. But yes, your points are my biggest problems, however I do believe they can be fixed. I am considering, as you said, multiple columns, and other things

I am glad to see so much feedback! Keep it coming, I really want all pros and cons on the table before i commit to this 🙂