I had a thread in the SSS Ambassador section on the forums and now it's gone!

What happened to it?

What was the thread about? It may have been moved

http://subeta.net/forums/view/864874 your thread is right there still in the event forum

[edit] Yeah if you offered any hints or clues to the quiz it was probably moved/deleted.

You mean this thread?

If you ever need to find a topic you made, just go to your profile and click either 'Recent Topics' or 'Recent Posts'.