They broke public private crypto keys allowing to patch pretty much everything. It makes the usb dongles useless because now everything can be signed including ps3 updates (yet to be seen but possible). Meaning we can modify updates to include the payload and keep our ps3's up to date and running (now) signed code that we have made on our own.
They broke the chain of trust because one of the bootloaders implemented a broken crypto algorithm which returns as "random" input always the same data.
Hence they are able to modify the revoked list which means there is no downgrade protection and they are able to retrieve any key, thus sign any file they want = true custom firmware, you can run your own bootloader which allows you to run linux or whatever you want just by powering on your ps3 without redoing the usb exploit every time. They will present the demo tomorrow.
not exactly, the xkcd comic was kind of a joke. it wasn't that it returned the same number it was that it used the same random number twice making it computationally possible to calculate the unknown. I'm sure the number changes but when you can calculate it every time it doesn't really matter.