I think it would be interesting if Nielsen's BookScan unit installed tracking chips randomly on books, to measure reading trends.
This would tell us:
1. How much time people spend with their books opened.
2. How many books are never opened or read.
3. How many books are opened repeatedly.
4. How many books seem to be read more than once.
5. How many books are only read at night.
6. How many books are only read during commuting time.
7 Which pages people like to linger on.
8. Which books seem to be read immediately following other books.
Of course, we already do this (and more) on websites, and the more that devices like the iPad and Kindle catch on, the more information like this we'll know about peoples' reading habits in general. Going forward, I think there need to be better disclosures on websites and products about what information is collected, because (1) people ought to have a better understanding about what type of footprint they leave, and (2) businesses, schools and charities need to have a better understanding of what type of information they should be gathering, and how they should be using it.