Stealth Mode (In The Forums)

[cookderosa]

I was curious, is there a stealth mode option for the forums? I don't see it...
It's weird, but I feel that some people are in stealth mode when I see their responses.

They're online and they're offline, a few seconds later, they're on again.
For me, I'm either online or off, and it shows up on the bottom of screen.

And yeah, for my 1888th post, I'm asking "this"... what a waste of a post! eh?
Update: Nevermind, I found it, the "invisibility mode"... cool...

I didn't know there was an invisibility mode!? I don't think I've ever signed out.