Interesting comments from TadW about US vs Europe and push content, will try to find out answer to this, maybe they will have one server in Eirope, one in Us and one in Asia, to cover all three markets they are aiming at.
I would doubt that the whole of the hardwired ID is transmitted, it is instead used as a means of verifying identity, It is I believe more in the form of a hardwired decryption key that allows documents to be unlocked and viewed. Push delivered subscription publications sent to the iLiad from the IDS server will be encoded so that they can only be read on the device belonging to the subscriber.
The transmission of data from the iLiad to the IDS server is probably encoded and uses the reader ID as the decryption key. I was informed that it uses full 128bit encryption.
Yes it does suport viewing PDF and from what I have seen it would seem to support PDFs created at least up until Acrobat 5.0, since it fully supports hyperlinks within a PDF. This is significantly better than the Sony which only uses the mobile version of PDF which does not support hyperlinks.
I am uncertain about whether it can read chm files, it can certainly handle HTML and XML.