The site was updated this morning in anticipation of CES. You can't actually do anything other than wander around. The reader software is not yet available for download, and the Blio bookstore won't open until February.
But the site does list the hardware and software needs for Blio. The minumum requirement is WinXP, Vista, or Win7 on a 1.6GHz CPU. There is no mention of OSX or any hand held devices. Given the OS requirements, a dedicated reader is out of the question.
The FAQ hints at some of the things you can do with Blio: bookmark, TTS, and annotate with notes, images, and audio/video clips. Blio will also support direct download of content from such sites as PG, Feedbooks, and Munsey's.
I'm somewhat relieved. With all the rumors flying around before the announcement, I was worried that a new format will add to the tower of e-babel. I don't think we'll have to worry about the Blio doing that. Given the high support requirements, it probably won't catch on and hopefully die a quiet death in a couple years.