I enjoy the fact that I can go into any eGO server and I can see people that I've met here on the forums. Then, through them, I can meet everyone else on that server from eGO. It is an all-inclusive, welcoming, friendly atmosphere. Few organizations that are this big, or even close to this big, have such brotherhood between divisions. I can disconnect from a CS:S server, where I know a lot of people, get on a DoD:S or TF2 server and say "whats up?" in admin chat and plenty of people will say "hey ginger hows it going?"
I also love going to other servers and hearing the kickass raging that non-eGO players get sucked into. Nothing better than hearing a pub rage about eGO and quietly laughing to myself about it, and then putting a bullet in his head and watching "[insert player name here] has disconnected."