Longboarders have reached records of 80 miles per hour down highways and even down highway roads in mountains and even passing cars. Longboarding can cause serious injury though because most don't wear any protection and usually have injuries because they hit cars, signs, or just the road.
Freerides just mean from going from one place to another with very little tricks.
Downhill is when you start at the top of large hills and go down as fast as possible
Surfers would "Dance" on their board while surfing like moving to the very from of the board or be crazier and do handstands and other things on their board.