A recent study by the social media management company Virtue has shown that the biggest spikes in Facebook channels maintained by companies and brands occur at 11am, 3pm and 8pm (ET) on weekdays, with the biggest of the three at 3pm (Wednesdays are the busiest days, Sundays the quietest).

Readers of Jean-Paul Sartre might recall what the French writer said of 3pm, how it is the "worst time of day" because it is "too late to start something, too soon to finish."