What are people usually doing....

[Gopher]

....when the screen tells us that they're perfoming an unknown action? Any ideas?

[Sportsdude]

I have no idea.

[purelife]

No clue.  I'm confused.

[Gopher]

Glad to know I'm not alone.  

[purelife]

I saw that too when I check to see who's online and get

"nothing, or nothing that you can see..." and have wondered what they would have to be doing to get that.  That's kind of cool.

[Gopher]

More than cool - it's brilliant. Something like everyone knowing you're carrying out  what could be a subversive act, but nobody being certain what it is.

[purelife]

It was definitely a stroke of genius on Teh Borken's part?

[Some Chick]

Normally it will tell you what topic someone is reading or posting in, or if they're viewing member profiles.

[weird al]

I think "perfoming an unknown action" would refer to anything performed by the autonomic nervous system, such as peristalsis, glandular secretions or, well, anything secretive I guess.