It is "preferred Player" or "Avoid this player". I have submitted "preferred Player" for you and Pacman, since you guys are new to XBL.
U can see I have 5 stars. There was a point where I had 5 then 4(dropped out of a Lost Planet Multi demo game and someone gave me a "avoid this player" what a dick). But I was able to get it back to 5. I have seen some people have 7 stars. You can see in my gamercard that there is room for 2 or 3 more stars.
DeafGamersOnline.com XBL GT: XDG Deaf Smith