It is part of the "Living World " content patches the game receives every 2 weeks. This will end what they are calling the Season One Finale on March 4th.
From my understanding, they are going into a 4 season content this year, a feature-build update and 2 big background projects in 2014. Previously when GW2 first opened up within the first eight months alone they pumped in 8 major releases then the next 4 months they pumped in another 8 major releases into the game. So far they added about 5 times in updates compared to a typical MMO.
Now you being a WoW player and like to do raids, they do not do raids in GW2. They do make up for it in the game but I never played WoW so I cant say if not having a raids in GW2 is a bad thing. What I can say, with Arenanet and what they have done with GW2 has worked so far. They are now going from a 300 dev team to now 350 devs.
Now the numbers from year one are below but they recently said they are now at 5 million copies sold and focusing on the expansion into China this year.
It's a great game that I do enjoy. It;s not for everybody but I do have a blast every-time I play and have tons of in game friends and guildies. There is always something to do. I really enjoy the WvW but I do play allot of the content PvE. Sometimes I wish there was more time to do both in a day but I try to do what I can when time allows it.