Sport Climbing Ethical History

Here is a quick sum-up of how sport climbing and its ethics have developed throughout the years. At the beginning of the era, ethics was copied from trad climbing and has later been made more liberal. The mentioned years from 1980 are all estimations.

1975: Kurt Albert painted red dots on the climbs he had "redpointed" in Frankenjura
1978: Jaques Nosley started bolting while rappelling in France
1980: French climbers left the gear while projecting
1985: Hang-dogging routes instead of being lowered down
1985: The use of chalk got popular
1995: Ok to onsight with quickdraws in place
2000: OK to belay and look down and later claim onsight
2005: Peak for multiple pre-clipped quickdraws and down climbing ethics
2010: Everyone has at least two pre-clipped carabiners

Here you have the original 8a ethics and practice article with some more details from 2001. The biggest problem I see and hear about today is having a tight belay stopping the swing when a climber swings out. Such ascents should not be valid even if it is not the fault of the climber.