Do you mean this thread?

http://www.flyertalk.com/forum/showthread.php?t=766645

I guess the mod "upgraded" your thread to a Sticky and somehow the thread number changed. When I used the linked you provided, it came up with nothing. But I was able to find the thread (#766645) started by you under Avis forum.

I recalled reading somewhere for those FTers who are either newbies or with fewer than 5(?) posts, when they post with links/referral/...etc, those posts are flagged by default as some kind of anti-spam mechanism. Those posts/threads won't be up until mods "unlock" them. I guess that's what had happened to you.

No idea why the thread number changed though.