Submission is a move type that has always been available. Submissions are considered to be a mini-game style move, similar to pins. Submissions can make people tap out, thus losing the match. The Submission system was upgraded in WWE '12, with the addition of the limb targeting system and the new breaking point submission system.
Prior to WWE '12Edit
Before WWE '12, submissions were very different, the 'submissioner' would pull LS back to apply pressure, than move LS slightly back and forth to make the 'submitee' tap out.
WWE '12 and overEdit
WWE '12 greatly improved submissions, submissions are now a tug-of-war style mini-game where both the submissioner and submitee rapidly pushed A, B, X, and Y. (X, Square, Circle, and Triangle on PS3) to try and fill (submissioner) or deplete (submitee) the 'Breaking Point' bar until the submission is either broken or the submitee taps out.