The spoon is one of the oldest eating implements, much older than the fork. Its modern English name derives from the Anglo Saxon word spon, referring to a thin concave piece of wood used to dip into porridge or other somewhat thick liquids that couldn't simply be drunk from a bowl. Until the seventeenth century in England people ate with fingers or spoon; only around 1670 did the fork come into vogue. In Thailand, as in some other Asian countries, the spoon as a dining implement is a fairly recent innovation. Thai people ate with their hands until the twentieth century, when the government exhorted them to use spoons and forks in order to appear "civilized" (read: westernized). Spoons are the main eating utensil in Thailand today, with forks serving mainly to push food onto spoons, an arrangement which I have become quite enamoured of. In Thailand, contrary to popular belief, chopsticks are only used to eat noodles.
The spoon used to reflect social class in Europe: the poor used wood, merchants clasped pewter, while the wealthy handled silver spoons. People had only one spoon which they wiped down between meals, and if they went out to eat, they took their spoon with them. The expression "born with a silver spoon in his/her mouth" derives from the custom of giving an infant a spoon at baptism: again, silver for the aristocracy, but wood or horn for a peasant.
An odd hobby is spoon collecting, which apparently began in 1890 in Massachusetts, when a jeweller introduced a sterling silver spoon which commemorated, of all things, the Salem witch trials. He sold 7000 the first year. Today it's an international obsession for matrons named Mary.
There are many shapes and sizes of spoons. The most common are the teaspoon, tablespoon, soup spoon, and serving spoon. Tea- and tablespoons have oval bowls, while soup spoons have round bowls. Proper soup spoon etiquette dictates that you always fill the spoon by moving it through the soup away from you, not towards you, and imbibe the soup by sipping from the edge of the spoon bowl, not placing the whole spoon in your mouth.
Specialized spoons are many, and include the long narrow marrow spoon used to scoop the marrow out of bones in dishes like osso buco, and the caviar spoon, which is made out of shell or gold, as eggs will tarnish silver.
Wooden spoons are mostly used today for cooking, and should not be run through a dishwasher. Instead, clean quickly and dry after each use.
What does it mean when a recipe advises cooking an egg-based custard until it coats the back of a spoon? The mixture should leave an even film on the spoon when it's removed, such that if you run your finger across the coating on the spoon, it leaves a clear trail. If the coating runs into the trail, the mixture needs to be cooked more.
Some of this information is from the column "Social Studies", a fascinating daily miscellany found on the back page of the first section of the Globe and Mail, "Canada's National Newspaper".