I noticed in this PvP video that he had several unusual icons over his head as well his party members heads showed icons also. I realized that these were the skill icons of the skills the players were performing at the time. So I went out to figure out these icons and how to configure them. I found that in the UI options there are several options to turn these icons on for not only seeing the icons over your own head but to see those icons of your party members as well. (They are off by default.) These come in quite handy for PvP as well as PvE. They indicate not only what skills are being used but information such as if someone has pulled aggro, a monster has enraged, someone has just taken a large percentage of their health in damage, or if someone is at low health. Follow the link below for full guide on the icons and their meanings.