Back in 2011, with the release of Modern Warfare 3, Activation announced whole new separate social media service that promised many things when you subscribed to it such as clan and stats tracking, exclusive video series, weapon guides, and early access to DLC. When the final product was showcase to the public, it was straight-up broken and it was naggingly hard to navigate through the menus. Even CEO of Activision, Bobby Kotick admitted that it was broken and that he didn't care much for the people complaining about the service.
When people realized about how crappy the application real was,they ditched the product and went along playing their games. When Black Ops 2 arose to the public, Call of Duty Elite had switched from an paid premium membership to a free service. But it was already too late, as people didn't care much for it anymore after having such a bad experience the first time around.
Now, three years later, Activision announced that Call of Duty Elite will be shutdown for good on February 28th for all platforms including Consoles, PC, and mobile devices. Stats for Modern Warfare 3 and Black Ops 2 will be saved in-game, but as for the clans and rewards people have worked tooth and nail for, they will be gone.
But if you still want something outside of Call of Duty to track your stats and clans, the Call of Duty App is available throughout all iOS and Android devices.
Honestly, I total forgot about Call of Duty Elite existence quickly after I found out how lousy the service was presented. If this announcement was never made, I would have just assume the service closed down.
Any dieding questions about Call of Duty Elite closing can be found here.