The Call of Duty Elite service allows players to view a full range of statistics of their game play including kill/death data, ratios, heat maps, frequent body as well as the ability to join clans and participate in competitions.
Since Modern Warfare 3's launch on Tuesday, the service has been overwhelmed with demand and has not be available. According the status site, on launch day, the registration and login servers were of such high demand, they crashed out leaving some new users unable to register to the service. Since then those servers have been extended however the main servers are still being extended and updated keeping users from viewing their stats either via the website, or the on-console apps.
To keep up-to-date with the current service status, keep an eye on this site:
I commend the Elite service for remaining transparent about the issue with frequent updates and detailed updates at that.