a) People didn't make gold. b) Most of the Earth's gold lies at its core, the metal's high density having made it sink there in the planet's youth. Virtually all discovered gold is considered to have been deposited later by meteorites that contained the element, with the asteroid that formed Vredefort crater having been implicated in the formation of the largest gold mining region on earth, Witwatersrand basin (http://en.wikipedia.org/wiki/Gold) c) Gold has always been present as a mineral in the rocks of earth. Gold was formed in small amounts by nuclear fusion in stars and was "distributed" across space by a super nova however due to its neutron rich construction, most gold was probably originally formed in neutron star explosions or collisions, itself relatively rare. This may explain gold's relative rarity. When earth formed, gold was included in the substance that accreted to make up this planet we're on. (http://wiki.answers.com/Q/What_is_the_origin_of_gold)
Gold was mined by man since 40,000 B.C. Archaeological digs imply the use of Gold started in the Middle East where the first known civilizations started. You can read more about the history of gold at http://bullion.nwtmint.com/gold_history.php.