Skate 3 doesn't take place in the hometown of the player. Instead you have moved to a new city to start a skateboarding company. There are still a few locations that will feel similar to ones from the previous game, like the starter school, but overall it is new (and for the better).
The main character's goal is supposed to build his own skateboard company from the ground up. You have to complete photo shoots, take videos, and win competitions in order to sell boards. By selling boards, you unlock new competitions as well as new clothing and boards. There is also an added Park Editor.