It could actually just be a system that is set up to look through things like forums and on the internet (since you can find peoples gamer tags through google searches), probably also using things like battle net and it is just typing in the name and sending a generic message to people hoping someone will be interested in their spam, which i doubt anyone would be (free xbox my butt, what fool would believe that). It will probably quickly go away once they realize that people arent taking the bait (will cost more to keep doing then they are making), or microsoft will shut them down, either way i doubt we will have to worry about it for much longer.