Re: Why is this the 'AT&T Atrix' Thread and not the 'Motorola Atr
It's most likely because the Atrix has only been released on AT&T, so it's specific to AT&T. If you take a closer look at the organization of the forums, you'll notice that the HTC Sensation forum is listed as "HTC Sensation", with sub-forums for "T-Mobile Sensation" and for "Vodaphone Sensation". Same thing with the HTC Merge forums. It's just "HTC Merge", with sub-forums titled "US Cellular Merge" and "Alltel Merge".
However, take a look at the "Sprint HTC Evo" title. It includes Sprint in the name because Sprint is, so far, the only carrier to have an Evo phone, technically.
It's basically just which phones are exclusive to which carriers. If they're exclusive, (meaning only that carrier has it), then the thread is titled with the carrier's name involved.
edit: Well, that's true, I suppose Bell carries the Atrix, though that's not a US Carrier.