dcheney - 1:50 am on Feb 7, 2010 (gmt 0)
As someone that frequently uses quite obscure books in my daily research, let me say a word about "opt-out".
The problem with a very large number of books is that there is no easy way to determine 1) who owns the copyright and 2) how to reach them.
Book publishers have come and gone and merged a lot in the last 90 years. So even contacting the publisher is often a difficult task.
Authors move and die (not like most books have addresses for the author anyway).
If "opt-in" is required, this very large number of books will never become available digitally.
I have no problem with there being a requirement that a reasonable attempt be made to find the copyright holder. I don't even have a problem with "opt-in" for anything written in the last 50 years (with that 50 years sliding ahead as time passes). I have no problem for paying for access to the books. But I would hate to see that large quantity of books rarely or never being found because of a mandatory "opt-in" policy.