What happens if i clear all cookie data ?

[AC Question]

What will i lose exactly?

 

[Rukbat]

Cookies store the data for a particular website (each cookie stores data for its site). If you have "remember me" or "keep me logged in" checked on a site, that's in the site's cookie. That's the kind of stuff you'll lose. (You'll also lose the name, address, etc., that the site may fill in automatically for you.)