Simutronics, developers of MMO dev platform HeroEngine announced during the Games Developers Conference in San Francisco that their engine is capable of supporting up to 100,000 concurrent users on a single shard. The thing to note here is that BioWare is using HeroEngine to develop and deploy SW:TOR. This could be interesting because if the servers are capable of supporting such large numbers of users we could be seeing less or no queues on more populated servers. This could help avoid one of the most nerve wracking moments in MMOs called launch day queues. I don’t think I can handle another queue screen after waiting eagerly for the game to launch for months/years.

I am not sure though if a single shard holds the whole server (game world) or just a particular part of the game world. Maybe some more tech savvy person than me could decipher this from the source article at GamaSutra.