My postulation is they will discuss the WiiU and it's various security measures, with a probable demonstration of their circumvention, without a thorough indication of how their exploit(s) work or an actual release of anything "important" for WiiU homebrew. As has been explained by the team in the past, there are perfectly good reasons for them not releasing their work, so it's most likely just going to be demonstrating that they can get around the security and presumably giving some vague details (it is a hacking conference after all, simply showing their work isn't going to cut it with most attendees; there'll have to be some technical discussion).
Of course, they could surprise me and announce the release of a full homebrew launcher and SDK for the WiiU or something. But it's hard to see why they would.
Then there's the slightly more likely (but still not overly likely, in my opinion) "middle ground" of them releasing a Linux kernel + loader for WiiU mode, which in theory wouldn't allow piracy (all custom code would be running on Linux kernel, so it wouldn't be "native" WiiU code, so safe from piracy) but could allow some useful stuff for some people (e.g. media players etc.).
Time will tell, I guess. Still about a month and a half off, no real point in speculating too much at this point.
