David Boies is the same lawyer who pushed for a Microsoft break-up in the anti-trust case that was started by DoJ about a decade ago - and now he's working for B&N, helping them get once more DoJ involved and maybe even turn this into another anti-trust case. B&N has accused Microsoft before that what they are doing with their trivial patents for which they demand high license fees is very anti-competitive.
Microsoft has just escaped the decade long anti-trust monitoring earlier this year, and since then they've become a lot bolder in their actions, like gunning for Android manufacturers with their chest of patents that they aren't even disclosing, buying Skype for $8 billion, and so on. Under the anti-trust monitoring, these probably wouldn't fly, but now they do.
If Microsoft would be put once again under anti-trust monitoring, it would be pretty bad for them especially now that they risk losing everything with the transition to the much different Windows 8, because most users won't be used to this whole new Windows interface (but that's for another discussion).
The point of this is also to bring a lot of high profile attention to the case, and put Microsoft's patents and their licensing deals under a microscope. I have a feeling that the more we learn about Microsoft's secret deals with the manufacturers, the more Microsoft will be in a weaker position, and eventually DoJ might even order them to backtrack on this, just like they did when Microsoft wanted the Novell patents.