What does it mean ? Simple now you need not to login in both IE and Firefox in any of the online website you access or open IE only when a site says It supports only IE. We had talked about IE Tab which is an add-on in Firefox to view sites which are IE only.
Coral IE Tab is like IE Tab but uses an embedded IE Engine which can sync cookies between IE and Firefox so you need not to login when you open the same page in IE tab in Firefox.
This becomes very useful where you need not to do too many step when you switch your browser. Apart from this Coral tab supports Adblock Plus. Also If you feel like not sharing the cookie, you can just right click and set to open in IE Tab without cookie sharing.