Getting back on topic:

In your opinion, should we do something special? If yes, what? Perhaps an "open bar" at our office on a particular day?

Ok, I admit, as we want this to pass by without fireworks and a marching band, we are thinking about something discrete: the owner of a domain name who reaches the 500,000-mark will be totally refunded his or her purchase (whatever the length), and, as a cherry on top, he/she will get 5 of the new Gandi t-shirts fresh off the press :)

What, have I just made another subtle announcement? ;)