You can track it in-browser with cookies. You can track it in-browser and have it remain when the user clears cookies with offline storage. You can track it i

You can track it in-browser with cookies. You can track it in-browser and have it remain when the user clears cookies with offline storage. You can track it in-browser and cross browser on the same PC and have it remain when the user clears cookies with flash cookies. When a user logs out, you can store the account fingerprint used in all 3 of those places and maintain it as another account logs in. Combine them all and it's pretty effective.