It’s 100 years later in the world of Tyria, in the kingdoms of Ascalon and Kryta - the original Guild Wars: Prophecies setting. The same key tenets of gameplay remain in place, but much has changed alongside the ever more sparkly graphics; not least that everything seems… well… persistent. Up until the advent of the sequel, when you ventured outside a settlement there wasn’t much chance of bumping into a friend.
No chance actually - you and your party would meet up, then fight through an instanced zone. Loads of other people could well be fighting there, but you’d be in a curtained-off, parallel dimension, and never the two would meet. Guild Wars 2, however, will take place in a fully persistent world - and still won’t ask you for any fees.