Actually it is borderline useless at the moment as if you look at the enclosed video, it gives you correct vector direction only at certain range and only when in freeview and when not in freeview then it gets limited to horizontal data change only.
http://www.youtube.com/watch?v=6g3A1jl1Otg
Can of redbull indicates where you supposedly look. As you can see it only sometimes corresponds with where you actually look on your screen