I also wonder how much load it can carry: How many visitors can it serve running as a web server and how many clients can it host as an email server? Or is it even possible to put figures on such stuff?
I think it will also make for a nifty testbed/development platform for new upstart entrepreneurs. Now that they can get SL Server plus hardware at a ridiculous low price. It will be interesting to see how people put this Mini to use.
Oh yes, and it makes WHS look like a leper.