That much said, the more modern day definition of surfing tends to refer to when a surfer rides a wave standing up on a surfboard, which is referred to as stand-up surfing or paddleboarding. Although, another prominent form of surfing in the ocean today includes bodyboarding, which refers to when a surfer rides a wave either on the belly, dropknee, or stand-up on a bodyboard. Not to mention, knee boarding, surfmatting (riding inflatable mats), foils, bodysurfing, and so forth.
Three major subdivisions within sitting -up surfing are longboarding, shortboarding, and stand up paddle surfing (SUP), reflecting differences in board design, including surfboard length, riding style, and the kind of wave that is ridden.
In tow-in surfing (most often, but not exclusively, associated with big wave surfing), a motorized water vehicle, such as a personal watercraft, tows the surfer into the wave front, helping the surfer match a large wave's higher speed, which is generally a higher speed than a self-propelled surfer can obtain.
Recently with the use of V-drive boats, wakesurfing, in which one surfs on the wake of a boat, has emerged.
The Guinness Book of World Records recognized a 78 foot wave ride filmed by ESPN as the largest wave ever surfed.
Source: Wikipedia, Facebook