In light of the release for Forza Horizon 2, the Forza Hub (picture from reddit.com) is available for free today off Xbox One where you can receive in-game cars and credits for the game (and Forza Motorsport 5) absolutely free just for logging in. The comparison to Halo Waypoint for Forza Horizon would not be far-fetched.
At only 26.19 MB, the Forza Hub will also have the latest game news and you can enter in-game events straight from the app. You can also compare your progress in the game to your friend.
Forza Horizon 2 releases today in North America and on October 3 in the UK, and I surprised even myself by giving it a high score in my review.