Producer/Director Yoshi has verified that after billing begins, FFXIV will be having a server merge. There has been a lot of debate on the official forums about this topic.
First things first; if you have no one to play with in an MMO, it's no longer an MMO, and the situation must be rectified immediately. With 2.0 far from being a reality, as well as billing starting soon, the server populations are going to dwindle. That's common sense. What better way to give us people to play with than a server merge?
However, server merges can also look bad to those who aren't privy to the details of what's going on with this game. Hearing the words "server merge" can gear your thoughts to a dying game. However, people who are considering trying out the game for the first time already know the game's poor reputation, and will probably not be scared off by the words "server merge". Those people have been scared away already.
As for a dying game, we do not believe that is the case here. The development team is working hard to keep us involved in the game, and keeping us busy until the release of 2.0. Version 2.0 will be a rebirth of the game, and a server merge in this situation is a temporary solution to a problem that (if the game is advertised correctly and launched the way it should be) will no longer exist after 2.0's release.
This merge will not be an automatic switch. The way the post is worded, it sounds like, based on server populations, that those on lower population servers will get to choose from several other servers to transfer to. Hopefully everyone will have plenty of notice so that they can speak with their linkshells and other friends and coordinate the merge.
This merge also leads to many more questions. What happens when 2.0 comes out? Does everyone get reshuffled, or will new players be put in new servers and old stay in old? What happens to those that were playing, but are taking a break until 2.0? Will they get to choose to join their friends on a specific server when they come back? Hopefully we'll find out soon.