I found a cool trick
If you go to your forum posts you get a url like this
but what you can do is add this to the end of the url
Keep increasing the page number until you get no forum posts, this means you went too far.
I was able to do this to find thibault's first forum post
You can do this to any account.
This doesn't work for any post after 10,000 (You can't go beyond 1,000 pages)
You can't post in the forums yet. Play some games!