Whether you’re doing PvP or just plain killing PvE mobs, it’s very handy to know who’s targeting you. (This is fun, too, because it’s also a way to spy on who’s inspecting you “in secret”).
You don’t even need extra plugins – it’s just a matter of changing the settings to obtain this result.
All you have to do is to is to enter Settings (either by using Escape or clicking on the computer icon on your toolbar).
Choose Interface – Combat.
Switch Target of Target on.
In the future, when you target somebody, you can see, whom he’s watching.