Multiplayer is a feature introduced in the first game that has evolved a lot.
The first game was basically the prototype for the next two. It had three modes of online play: ranked match, unranked match, and online Freeskate. Ranked match had you choose from multiple game archetypes, such as Jam, S.K.A.T.E, and spot battle, and have you compete. When the match ends, you earn experience, which contributes to total experience amounts. Xp totals are seperate in Trick games and Deathrace games. When you reach a certain amount, you rank up. There are five ranks in both categories: Unknown, Amature, Pro, Icon, and Legend. Unknown is where you start on each, and the others are reached at certain xp milestones. Unranked match is almost exactly like ranked match, except there isn't the xp system. Online Freeskate is what it says it is: you choose an area, and it spawns you either in a joinable game or a new game if it can't find one in the area you searched. You can also star a private game, and invite friends as needed. there is also offline play labeled as Party Play. It doesn't have Freeskate, however, and there is a limited amount of game options.
Skate two has the same structure as the first, but there are three major differences. First off, there is and option to jump into a game at anytime in Freeskate or Career by pressing the Back button or the SELECT button. Second, there is a new Ranked/Unranked mode called Hall of Meat. It has players try to get the highest HoM score possibe in numerous areas, trying to beat each other's scores. The third improvement is the addition of Freeskate Activities. These are challenges that have various conditions such as making a certain number of gaps or doing a trick simultaniously with the other players. There is an acheivement/trophy for completing all of them.
The third game has all of the features of the second. Minor tweaks such as the ability to propose a seperate game type to major additions such as online teams are present. Party Play was removed, but returned later as DLC.