Active players have another shot at taming a free grey wolf or earning a "Noble Hero" costume set during the anniversary. There's also a few special NPCs who will be accepting anniversary coins in exchange for an array of special goodies. If you're of a mind to spend some money, all of the item shops wares are available for 20% off through the 13th.
GPotato is also giving veteran players 250 premium crystals and an anniversary gift package for those who have been in the game prior to today. The anniversary event goes from now until June 10th.