Derek Thompson in The Atlantic:
Praise and sympathy: They are two of life’s essentials, the oxygen and carbon dioxide of social interaction. The first is most directly elicited by bragging, and the second, by complaining. The humblebrag—e.g. I’m exhausted from Memorial Day weekend; it’s soooo hard to get out of Nantucket—sits at the center of these competing needs. It is a boast in sheepish clothing, kvelling dressed in kvetch. And, like nearly all forms of multi-tasking, the drive to satisfy two goals at once typically results in double-failure.
“Two fundamental goals in life are to get people to be impressed by us and feel sympathy for us,” said Michael Norton, a professor at Harvard Business School and co-author of the paper Humblebragging: A Distinct–and Ineffective–Self-Presentation Strategy. “People think they can get the best of both worlds by being indirect. Instead they are perceived as insincere.”
False modesty is not a recent invention, as Jane Austen proves. But the humblebrag portmanteau, Norton said, might be a product of the social media age, due to the space limitations of platforms like Twitter. Stories that once cautiously mixed humility and boastfulness now appear, suddenly concentrated in the crucible of a Twitter box, to be inelegant attempts to disguise pride.