It's trivial to find stuff that almost certainly infringes, now that the patent has been granted as of 2007. One wonders how many letters Discovery Communications sent out to people requesting they pony up. For example:
Did they send a letter to the British Library?
ETA: Questia was founded in 1998 and therefore might possibly constitute prior art all by itself, altho they don't sell books, only access. Which might keep the British Library's service from being infringement. Altho I still don't see the non-obvious part going from subscribing and reading online to paying for a DRM'ed download. Especially since we've got prior art examples of paying for a DRM'ed download, just not from the makers of the reader. Can you _really_ just cut and paste entirely existing stuff together and call it a non-obvious idea? And then say that any conceivable variant on same is covered?
I fucking _hate_ patent law.
ETAYA: I am trying to figure out when academic journals started going online-only (but locked-down). I think it was sometime in the mid-1990s, but I'm having trouble finding out the exact dates. If I'm right, this should also help with prior art.