I like it. But I am confused. The forum doesn't show you your user ID during the registration. Did you create a different username and then PMed theymos and ask to have it changed after you created an account or what happened there?
I think it was probably just (cleverly) well timed. You can always see the latest new member at the bottom of the home page or the dedicated
stats page. I think the ID is simply incremented each time a new registration takes place, so you can predict what yours will be if you're quick enough.
Here's the registration timestamps:
(u=553627) September 09, 2015, 10:36:49 PM
(u=
553628) September 09, 2015, 10:41:21 PM
(u=553629) September 09, 2015, 10:46:20 PM
So in this case, there was a ~10 minute window (can't know that ahead of time obviously, have to get lucky) to create a new account and get the ID that you expected to.