Well, it's a rather long story. To cut it short: Wrong Pla.net wasn't actually ready for the big audience when it became public, because it was running (and still is) on the development machine. That's why it had some problems in the first day or two.
The reason why it wasn't available today for ~2 hours was the change of my IP which unfortunately happens irregular for my home-account ;-)
It's all back up and running fine now 8-)
@Wayne
Thank you for the offer but once we move to the "real" webspace there shouldn't arise such downtimes anymore :-D