Rob Walker in the New York Times Magazine:
FreeRice.com presents the visitor with a word and four choices as to what that word means. Click, learn the right answer and get another word. Correct answers lead to a higher score and harder words. It is, then, a “casual game,” the name given to a wide variety of electronic, computer or online games with a relatively simple structure and set of rules — a genre of diversion, not immersion. With tens of millions of regular players, “casual games are among the stickiest, most-sought-after content online,” according to a white paper posted on the site of the International Game Developers Association. The core texts of casual gaming are solitaire and Tetris. It’s a safe bet that a great deal of casual gaming occurs in the workplace, where it’s more discreet than paddle ball.
Because it is structured as a sort of rolling SAT vocabulary quiz, FreeRice.com laces your time-wasting with fresh knowledge. For example: “hircine” means “goatlike,” and “omphaloskepsis” means “navel contemplation.” Thus: self-improvement.
This brings us to the greater good. The site promises that every time you give a correct answer — that, say, “rubicund” doesn’t mean “hairless,” it means “ruddy” — you donate 20 grains of rice to feed the hungry by way of the United Nations’ World Food Program.