It may be ‘pulling the tail’ of the terms and conditions of a major context-sensitive advertising service to post this, so possibly I shouldn’t, but I just can’t get over the line ‘Control information even after it has been delivered‘ as seen in the advert above, which has appeared on this site a number of times in recent days.
The website of the advertiser in question states that its technology can ‘let you’:

* Control who can see information and whether they can print, copy, or select text
* Prevent information from being forwarded
* Recall or expire information, even after it’s accessed
* Track what recipients do with your information (For example, read, print) after they download it.

Can they actually ‘control information even after it’s been delivered’, though? Sure, they know whose account was used to print the document that’s been ‘recalled’ or ‘expired’, but do they know whether he or she kept that printed copy? Can they tell who was looking over your shoulder when you read that information? Can they cause the printed copy of the ‘expired’ information to self-combust? (or maybe send in a squad of ‘firemen‘ to deal with it?) Can they erase your memory?
I’m reminded of a note in a ‘student handbook’ I received as an undergraduate at Brunel. It went something along the lines of “The University has to retain rights over all the IP you create as a student, and the right to withdraw or annul your degree, because it is the only real leverage we have over you. We can’t (yet) bulk-erase your brain.”
Still, the handbook was peppered with Zen & The Art of Motorcycle Maintenance references, which was nice.