How does the forum know you're on?

[PId6]

I've been on many forums and this has bothered my curiosity for a while now. On many forums, you can see whether a person is online or not (see little green/black light thing below each person's avatar). On some of them, you can even see what page the person is looking at. But how does it do that?

Now, I'm not too familiar with the internal workings of the internets, but it seems to me that when you access a page with your browser, shouldn't it just retrieve information from the website one time? The browser certainly isn't refreshing that information unless I manually refresh it, so it shouldn't be constantly retrieving new information from the website. How then, does the forum know that you're still viewing it?

[SilentNight]

I believe when you sign on it tells the server you're online until you either sign off or time out.

[SurlySeraph]

Because the Giant is watching you, citizen.

[Erloas]

Generally speaking I think it simply makes some guestimates based on the last page you have requested from the server. I'm sure if you openned a page and then left it open but didn't do anything with it for 2 hours and were somehow able to check your own status it wouldn't show you as being there.

Also if you opened 4 pages in a row and had them all open it would probably only show you as active in the last page you opened, rather then all 4 of them.

[PhoeKun]

I believe when you sign on it tells the server you're online until you either sign off or time out.

If you're set to sign in automatically, the "timer" begins when you make a post. I believe the window for the little light is somewhere between 10 to 15 minutes.

Of course, it could also be the bulletin board faeries.

[PId6]

Because the Giant is watching you, citizen.

^ +1

Thank you everyone, that will be all.

[bosssmiley]

The same way the radio station ident knows what you're listening to.