Not sure of course.... but I think what was meant originally is this.....
I can set this board in a way that it remembers me. So, every time I come here it recognizes me and I am in without having to sign in. But, now and then, mostly if something big on the board changes, it happens, that I come to such a board and it does not recognize me, I have to sign in again. In that situation I click again on the checkbox that it should remember me. As I said, this does not happen very often, but now and then... sometimes months apart....
I had to sign in a couple of times today. When I first came to the board, I had to sign in and then I minimized to my task bar (shhhhh don't tell the boss) and when I came back a couple of hours later, I had to login.
If you check "remember me" when you log in, and if you don't log out when you close the window at the end of a session, and if you don't clear your Internet cache or delete your cookies, then you will stay logged in and you won't have to log in again next time.