The term "pole position", as used in motorsports, comes from the horse racing term where the number one starter starts on the inside next to the inside pole. The term made its way, along with several other customs, to auto racing. In circuit motorsports, a driver has pole position when he or she starts a race at the front of the grid. This driver is referred to as the polesitter. Grid position is usually determined by a separate qualifying session where drivers try to set the fastest lap, or based on their position in the previous race(s). Different motorsports series use different formats for determining which driver has the opportunity to start from pole position.
Originally in F1, positions, including pole, were determined by lottery among the drivers. Prior to the inception of the Formula 1 World Championship, the first instance of grid positions being determined by qualifying times was in the 1934 Monaco Grand Prix. Since then, the FIA have introduced many different qualifying systems to F1. From the long standing one session on Friday and Saturday, to the current knockout style qualifying leaving 10 out of 24 drivers to battle for pole, there have been many changes to qualifying systems. Between 1996 and 2006, the FIA made six significant changes to the qualifying procedure, each with the intention of making the battle for pole more interesting to an F1 viewer at home.
Traditionally, pole was always occupied by the fastest driver due to low fuel qualifying. The race fuel qualifying era between 2003 - 2009 briefly changed this. Despite the changing formats, a driver attempting pole were required between 2003 - 2009 to do qualifying laps with the fuel they would use to start the race the next day. An underfuelled slower car and driver would therefore be able to take pole ahead of a better but heavier fueled car. In this situation, pole is not always advantageous to have in the race as the underfuelled driver would have to pit before their rivals for more fuel. With the race refueling ban introduced, this was no more and low fuel qualifying returned.
Also, when F1 enforced the 107% rule between 1996 and 2002, a driver's pole time might affect cars further down the track, as cars that could not get within 107% of the pole time were disqualified for the race. Since the reintroduction of the rule in 2011, this only applies to the quickest first session (Q1) time, not the pole time.