There's been an awful lot of community discussion around the first version of Microsoft's recently released Game Content Usage Rules. Most likely a result of Halo 3's upcoming Saved Films feature, Microsoft is the first game publisher to openly publish such rules, instead of simply remaining silent over copyright violations that do benefit them insofar as they help promote the games.
Shortly after the rules were noticed, some machinima studios claimed that its restrictions against "adding to the game universe" and prohibition against usic "music and audio effects" forced them to close down.
Don "DonkeyXote" McGowan in Micrsoft's legal department, who helped draft the rules, also posted in his blog about them, touching on the story, audio, and reverse engineering items specifically.
Machinima For Dummies has two news articles on the rules: one, two. Hugh Hancock provided an analysis of the rules, stating that they do need revision but are mostly positive.
However, probably the best analysis comes from EFF attorney Fred Von Lohmann, linked to in Hancock's post. The bottom line is: using this license is not mandatory, and even if you do use it, it provides rights additional rights to the fair use rights you already have.
