Facebook hours 

While a regular hour has sixty minutes, a Facebook-hour is usually shorter; due to the unnecessary amount of time spent on Facebook when one should be doing other activities.

It can vary from fifty minutes, all the way down to just fifteen minutes left on an hour.

Mark: Why did it take you five hours to do your math homework yesterday?

Tim: It took two and a half, actually, but was on Facebook half the time

Mark: Oh, so five Facebook hours?

Tim: Yes

Facebook hours by Norway90 March 21, 2011

Facebook Quiet Hours 

The hours of the night that begin somewhere around 11:30 PM and extend until mid-morning, when society frowns on interrupting a friend's late-night stalking or lurking on Facebook. Facebook feels quiet as a library, and you feel as though you are the only one on the entire site, because by this time your Live Feed has slowed to a halt. It is customary to ignore the presence of other online facebookers at this time unless they are very close friends, to allow everyone ample time for mindless late night facebooking, which may include but it not limited to Farmville, Mass Picture Stalking, or wall-to-wall reading.

Person 1: "Dude, last night I had 36 friends online, but I couldn't talk to them because it was during Facebook Quiet Hours."

Person 2: "Sucks. Same thing happened to me."

Facebook Quiet Hours by GingerSnapRayRay May 15, 2010