I'm late on this, but with the news that Amazon has bought the Advanced Book Exchange, it's not good news for the established used and rare booksellers out there.
Bibliofind is proof positive that things are gong to get tough out there for the second hand trade.
Obviously online sales are a pretty important revenue stream in used book stores and ABE already ticked off their vendors recently.
The homogenization argument is easy enough to make, but the dollars and cents aspect will make itself known first.
Posted by David