Need some suggestions about "community" :)

Just for fun I, and a few friends were going to make a community, started about an hour ago :) Haven't started with the design or anything yet, but I was thinking how the best way to handle users would be, or atleast what you can recommend, first I thought about having a database with users, and one with messages and stuff, and then I thought it might be smoother to create a database for each user, and store all his/her things in it, what do you think? If there is any other good way, I'm also open for suggestions :) Håkan