Well when I hear the word "gank" I tend to think of someone who is doing one of the following:

1) Camping Lowbie zones
2) Camping quest hubs
3) Bank NPC killers
4) The sort that waits until you are engaged w/ an NPC, specifically when resources are low.
5) specifically going out of their way to make life miserable for other players.

There is a big difference between this and your run-of-the-mill pvp. I was born and bred on a pvp server and I wouldn't change that. However, that does NOT preclude the possibility of NOT being as ass about it. I know I'll never win over my entire server but I will always advocate for self-imposed rules for honorable pvp. Yes, I said it. I'm deluded, clearly. ;-D

Now, I know that's not what "Gank" means directly but those who champion it tend to be the same sort that pull the childish stuff as well. The thread in question mentions the flags and other things designed to humiliate the fallen. That falls into the "punking" zone of pvp in my opinion, which is just one opinion. :)