Ganking is a No-No
When it comes to playing any MMORPG, there are just some unspoken rules that you don't do. Ganking another player is one that actually happens quite often. Ganking is when a much higher level player comes along and wipes you out without warning, and then normally "camps" (stays right on top of your body) your corpse and kills you each time you resurrect. Usually, you get ganked in an area when you are already fighting a mob so that you have a hard time turning on the other player and killing them, yet they still get the kill point for you. Essentially, they are cheating to get their PvP kill point on a lower level player where they are certain to win the fight. The big issue with ganking is that it is not really considered acceptable in-game behavior for anyone - yet people still do it. Overall in the MMORPG gaming community, ganking is normally considered dishonorable and unfair, and usually just down right mean.
Of course, there are players out there who defend this practice and they say that they are playing by the rules. By rules, they mean that they aren't using bots or cheat codes or hacks to kill the other player, so they can do this as much as they want to without breaking any of the rules of the game itself. They also will argue that the lower level player will eventually get to a higher level and start to gank other lower level players, so it is a fair practice. Also, some of these people who love to gank lower level players do so because they know that the lower level players will have higher level friends that they will then call out to help them, thus providing a better fight for them. While this seems like a valid argument, it still is not considered cool or fair by any means in any MMO or MMORPG game.
There are two main types of gankers: those who do it just for the pure thrill of it every now and then, and those who make it their life-long goal. Some players will dedicate their entire time online to simply finding lower level players or players who are already in a compromised position to gank. They will strategically put themselves in areas of the game where there are lower level players that are sure to be preoccupied with grinding mobs for quests and then gank them as they engage an enemy mob. Other players will gank a few times and see that they don't get anything out of it, then move on for a bit. But, those who do this constantly will usually keep a pretty low profile while they are online because it doesn't take long for the word to get out that they like to gank people in the lower level areas.
Normally, those who love to gank other players for the pure sport of it also do it to the NPCs that are around the area as well so that the lower level players have no help there either - no matter if they are simple vendors or guards. They simply enjoy knowing that the person on the other end of the game is getting frustrated by knowing that they cannot do anything but die. Some games have tried to stop this practice by placing special restrictions on higher level players. Warhammer Online: Age of Reckoning is one of the most recent to do this, with higher level players that travel to lower areas and flag for RvR play being turned into chickens with only 1 hit point and 1 damage point, from a peck.