When they have "Moved" next to them, they're called "shadows", it shows people that their thread has been moved to the appropriate room for a number of reasons:

1. Admin are tidying the site up to make it more user friendly.
2. We're trying to get people to use the WHOLE site, to help everyone in the long run.
3. The shadows will be left for a while until people get used to it, so they don't think their posts have just been deleted and subsequently make useless posts asking where the original ones went.
4. Clicking on the links with "moved" next to them, takes you to the room the thread was moved to. We're hoping it'll help people get used to going around the site rather than posting eveything in GD.

Hope this helps