I just logged in, and about 30 sec. later you signed off. This isn't the first time I notice this. What's going on Anglagard?
The entry for a person in the "online" display will disappear after 30 minutes of idle time. Possibly anglagard left the site for the evening almost 30 minutes before you logged in. Or perhaps he is busy composing a lengthy post, and his session has appeared idle because he has not loaded a forum page during the last 30 minutes.
Please don't misinterpret the online list.