Quote Originally Posted by Shurrikhan View Post
WoW. You can play with any player from any region through their realm visitation system. Guilds and standard matchmaking are still limited to Battlegroups, but you can play with all players.

BDO. All one data NA/EU data center. All character and clan data is stored separately from servers. You pick the server to log in on based on whichever has best ping at that particular time. Some events and bonuses set to particular servers to draw relevant players, but generally it's just a matter of additional/excess servers being made or crunched as needed for ping, with a graduated transition of some three seconds as your server or mini-server is crunched or split.

B&S. Crunched to one NA/Oceania server and one EU server, with cross-connectivity. (Russia, China, Japan, and Korean clients all wholly separate entities.) Channels are made/crunched similar to above for purposes of ping.

GW2. Now uses only mega-servers for all gameplay intents and purposes. NA or EU. Separate instances made/crunched as needed.

Playing on an NA server on any of these MMOs I have access to nominally 50+ to 100% of players playing the same game, worldwide.
WoW, from what I read, has CRZ "Cross Realm Zoning" within in the data center as default. All others you mentioned use one Data Center. All those MMORPG automatically place you in a CRZ where as FFXIV's plan is to give players the choice to move to another world. SE isn't doing anything different, they are really just playing catch up.