a board cookie is one you get from gas stations... they taste like cardboard (though kids don't care, so yes, they'll attract kids.. the mice know to leave them alone though)


just kidding...
the forum can also be called a bulletin board, or "board" for short...

a cookie is a piece of data saved by your web browser as way for a server to identify you as someone who has been to that particular website before, and to save certain preferences such as who you logged in as, and other preferences

thus a board cookie is used by many bulletin board sites to keep track of what posts you haven't yet read on that site, and whether you wanted to stay logged in once you close the browser so you wouldn't have to sign in again.. that sort of thing..