Which forum? I haven't had that happen, but I have noticed on some forums that the posts move down the page rapidly. Decorating and Kitchens especially.

You can do a search for your ID and perhaps find them that way, although the GW search engine really stinks. There seems to be no rhyme or reason to the way found threads are listed. Recent ones could be on top, middle or at the end.

What I do is bookmark the thread I posted and then it's listed in my favorites.