Implementation detail The unique thing is that it's a single shard - that is, every player inhabits the same game world, and there's nothing to stop you interacting with, cooperating with or shooting in the face any other player (whereas in SW:TOR they need to be on "your server").
Big fan of EVE and a long-time player, along with some of my colleagues; one of whom, when I mentioned that SW:TOR was sharded, responded, "Why do people still make games like that in this day and age?"