This meme was first started by TheTentor, a Member of youtube that closed his account. Gottam is simply a part of "Gotta Move That Gear Up!" -a phrase that the engineer in TF2 uses as a voice command. If you do some splicing you'll get gottam. Gottam is usually a phrase that the Vagineer uses, which is a different meme created by J16FOX. People started to spam this voice command just like The Scout saying "NEED A DISPENSER HERE" and the heavy saying "Pootis Despenser here!" (not yet submitted) both other separate memes. Gottam was also the first Team Fortress 2 meme to ever be created.

GOTTAMcube

and A Song made with gottam

and a video Here

GOTTAM IS EVOLVING