. The first number is the total new messages since you last logged in. The number after the pipe, if there is one, is the number of new messages since you logged in just now. For instance, say you logged in and out at 1:00pm then logged in again at 2:00pm. Now you see a number like "4|2". That means there are a total of 4 new messages since 1:00pm and 2 of those are new since you just logged in (after 2:00pm).The session stays active up to 20 minutes as long as you keep your browser open. If you come here, go to another site for 10 minutes, then come back here, the session will still be active from the first login and the number of new posts will reflect that.
