Megaservers?
When visiting a map, it’s no longer the original instance of your server or an overflow. Now people are being thrown around on maps of the different servers so there can be balance in the population of all maps. And yes, this does mean that all the people around you are from different servers, very likely.
basically in a nutshell, when you go into an open world map instead of every server having its own instance, it start with 5 maps and tries to put every player in them unless all 5 fill up then a new instance will be create.
Think of it like everyone is put in an overflow essentially.
Server should technically try to put team mates, guild members friends and people from the same server on the same map but this is not always the case, this could be due to bugs or a side effect from maps filling up. hard to say.
They actually have applied the overflow system to all zones now. The NA / EU separation is still applicable (for general global networking reasons), and in WvW you still play on your HOME Server’s side (thus the selection at log in is still important in WvW).
Beyond that, any Open World zone you enter could have players from any server in them. There is apparently some “voodoo” connection magic behind the scenes that is suppose to keep you with Guild members and players on your friends list, but it works with varying success. You also cannot manually select what instance of a zone you want to load into (sans being in a party with someone in the known zone and selecting to join them…which works pretty well most of the time).
Anet is still reportedly tweaking the process to improve it and there are plenty of issues and complaints (Role Players unable to group together, no longer being able to easily track resource nodes so multiple characters can harvest them,, etc.) Overall however, I personally feel it is a vast improvement to the open world as the game seems much more populated. There are certainly things that could be improved and I think Anet is trying to gather some longer term data before making any drastic changes to fix some of the complaints.
Fate is just the weight of circumstances
That’s the way that lady luck dances