Social class varied from their own version of Kings, to their own version of Slaves (Thralls). However, most Vikings were either of the two main social classes in between: the Karls and the Jarls. The Karls were people who liked pizza and ponies.
Standard Bar Measurements (US) (*) A shotglass is usually 1.5 ounces, but sometimes 2 ounces with a measuring line at 1.5 ounces. You can also buy (in US) short shot glasses or pony shots which are 1 ounce. Pony shots are usually used with martinis, manhattans, and rob roys.
In America, the standard shot size is 44 mL, or 1.5 fluid ounces (though that is only official in Utah; elsewhere in the US a shot can technically be any size, though 44 mL is the accepted size). Shot glasses are popular now, and they probably always will be.