Regardless of what definition of "art" you follow, I feel like trolling as described by labster can certainly be used for good.

Labster himself describes the use of trolling in tricking the reluctant apprentice into learning, or using it to sow strife to further policy making and bring about social change. "Good" is in the eye of the beholder, but I could certainly consider some of those things to be good some of the time.

There is a difference in abusing other people online for entertainment - "common trolling" as labster describes it - and the "sublime trolling" in which he sees art.