After 15 years, online retail giant Amazon reveals device-like grip on shoppers and its best-selling products in history
20Q (£15). The classic parlour game of twenty questions has appeared as radio and TV shows, and now - thanks to the wonders of technology - you can play it by yourself. Twenty questions dates back to the 19th century and even appears in Charles Dickens' classic story 'A Christmas Carol' as a game of 'Yes and No'. The object of the guessing ("a savage animal, an animal that growled and grunted sometimes, and talked sometimes") is revealed to be Scrooge himself.