I am convinced by this
Sergey Brin of Google has an op-ed in today's New York Times, making the case for Google Books:
"But the vast majority of books ever written are not accessible to anyone except the most tenacious researchers at premier academic libraries. Books written after 1923 quickly disappear into a literary black hole. With rare exceptions, one can buy them only for the small number of years they are in print. After that, they are found only in a vanishing number of libraries and used book stores. As the years pass, contracts get lost and forgotten, authors and publishers disappear, the rights holders become impossible to track down." (from A Library to Last Forever)
Pretty convincing stuff. Read the whole thing.