You can now track all your Xbox Live achievements for Xbox One, Xbox 360, Windows 8.1, and Windows Phone 8 via your Xbox Live account. Microsoft's Larry Hryb, also known as Major Nelson, has tweeted a URL that allows you to track your achievements in one central location.
For example, I can now see my achievements for games that I have played on Windows 8.1, Windows Phone 8, and Xbox One. You can also see the last time you played a game and see the specific achievements you have unlocked. Pretty cool feature!
Apparently, in Rayman Jungle Run for Windows Phone, I have only earned four achievements. I have quite a ways to go. With this new ability to track all my achievements, I can see what achievements I have yet to unlock too. Head over to account.xbox.com/en-US/Achievements to track all your achievements!