From an economic point of view, gift giving ranks as one of the most inefficient of human activities. The reason is simple: most gifts are not quite what we would choose ourselves – so we value them at less than their purchase price.

But now the internet has a solution for the wanton destruction of human wealth that takes place every Christmas: online auctions. People have been recovering value from an unwanted gift since the dawn of time by re-wrapping it and giving it to somebody else – who probably also does not want it. But selling gifts online is far more efficient: the goods end up with someone who values them; and the original recipient gets cash to buy the thing he wanted in the first place.