That seemingly unintelligible string of numbers and letters attached to MS Point cards and Xbox Live Gold trials has an underlying code, a kind of system in place, a group of hackers found out yesterday. Using old claimed codes, this group was able to come up with an algorithm to generate new, valid code strings -- those who input the code got 160 MS Points and could refresh the site for more. Later, through a separate channel, hackers were able to exploit the algorithm to generate codes for a Halo: Reach Banshee Avatar prop.
This forum seems to be the origin point of the algorithm in question, where some users have claimed to have gathered hundreds of dollars in MS Points; current estimates put the total damage to Microsoft at over $1 million. Microsoft has since had the codes pulled, though we have to wonder if there's any other countermeasure the company could use to catch these individuals.
Honestly, we're a bit too busy staring at these awesome lightsabers we just got for our Avatar to worry about such things. Lightsabers that were, uh, totally acquired through legal, completely ethical means -- yeah, that's it.