Don't think this means they know who's top dog and are showing their respect. All aerobic exercises performed in front of computers are indications of Facebook Addiction Disorder.
Like alcoholics, Facebook addicts hide their behaviour and show extreme stress when they cannot get their 'hit' - for example, during a power failure or if they lose their phone charger. Other symptoms are lack of interest in colleagues (unless they're chatting to them on Facebook) and slovenliness (why bother showering? Friends can't smell you online).
Some offices spy on employees, but that leads to more subterfuge. The answer? Treats. Like puppies, humans respond to positive reinforcement. If a Facebook addict gets his report in on time, let him spend 20 minutes on Facebook. If he brings in new business, he gets to have a whole hour.
Helen Kirwan-Taylor - email@example.com.