In Diablo 3, what does "X Damage over Y Seconds" mean?
Solution 1:
Easily put, it means it does X% of damage over a period of Y seconds. Meaning to get 1s of Damage dealt, you have to do X/Y = [DMG]ps
P.S - For an afterthought, according to your example, 360% per 6 seconds, if it was 360% per 1s, that would be a total 2160% damage after 6s. Yeowch! (But overpowered much?)