What is the Guild Wars 2 map overflow, and how does it work?

Last night a friend and I wanted to play the game together. We had chosen the same server and were both standing in the same location but we could not find each other. We did however get a message saying:

"You have been moved to the Wayfarer Foothill overflow. You are queued to enter the map when you are ready."

How does this overflow work? I am confused why I can't find my friend on the map.

Solution 1:

Overflow servers are created when the zone or world you're attempting to join is full. They're basically just another zone instance that's made. When you try to join a world/zone that's full, you will automatically be placed in an overflow server. You can earn XP and other rewards as normal on an overflow server, and it will consider you "in queue" for the "main" zone and once space opens up, it'll ask you if you want to join the main zone.

You will receive 3 options when the main server is ready to accept you:

• Travel - This will take you to the main server
• Reenter queue - This will allow you to remain on the overflow server, placing you back into the queue. You will then receive the popup again when there is room on main.
• Leave queue - This will allow you to remain on the overflow server without constantly receiving a popup to ask if you would like to stay.

Additionally, if you let the timer on the popup run out before you make a choice, it will default to "Reenter queue", leaving you on the overflow server, which will give you a chance to leave later.

Solution 2:

As of the "Feature Pack" update in April 2014, all PvE maps (plus the Edge of the Mists WvW map) now use the "Megaserver System". Instead of having a single "home" instance of a zone per server (plus additional "overflow" instances when those home instances fill up), there will be as many instances of a zone as are needed to comfortably hold the number of players in the zone. New instances are dynamically created or removed as the population fluctuates.

When you enter a zone, the server decides which instance to place you in based on a number of factors including what instance your party or guild members are in, your language, and your home world.

Another way to describe the change is that every instance is now an overflow, and the concept of having a "main" instance for your home world has been removed.