Moderators sometimes move posts to more appropriate forums on the boards. For example, someone may ask about a restaurant in MK on the welcome board and a moderator may see it and move it to the more appropriate restaurants board. If you are wondering why you may see this post moved to the restaurants board but another post a little ways down abotu favorite counter service locations not moved, the answer is that Moderators are human, and busy!, so don't catch or have time to move every single post that is in the "wrong" location.
Or a lot of people come here and post about renting DVC points however this isn't the right board. They should be posting on the Rent/Trade sub-board of the DVC discussions
For future reference, you should be able to go to your menu bar and choose:
Quick Links >> Subscribed Threads
and it will show you all the threads you have posted to or started (assuming your profile is setup to automatically subscribe to threads you post in)