Threads changing position?

Hello Rick, just wondering, when I got back from my trip, I noticed that the threads on the forum weren't in the same position as when I left. Over the last few nights I have noticed some threads moving position also. Is this some problem specific to my computer, or, is there some change in the way the forum works, that is causing this? I keep track on a seperate piece of paper what threads I have read, just in case my computer acts up. Now with the threads moving position, my simple back up doesn't work anymore :-)