At some point in the future, BioWare will implement a "Challenge" system in Mass Effect 3's multiplayer. Players will be able to complete "hundreds of new multiplayer challenges" that sound a lot like mini-achievements. Successfully completing a challenge grants Challenge Points (think high-score, not in-game currency) and personal progression through said challenges can be monitored both in-game and on a forthcoming N7 HQ website. Additionally, gold-level challenges grant an exclusive title and banner upon completion, and can also be completed an unlimited number of times.
The existing bi-weekly "Operation: Enter-code-word-here" events will be replaced by weekly Challenge events that grant their prizes to individual players immediately, rather than granting global prizes on a delay as the current system does. No word on when these changes will be implemented.