This is a fascinating result. The equipment needed to reproduce is a bit extreme (femptosecond multi-watt lasers are not 'garden variety' by any means) and one wonders if the 'read' set-up could be made cost effectively than the 'write' set-up. I would hope that Google would invest in a system to copy all of the books they've scanned into such crystals.

That said, I could imagine offering something like a web 'snapshot' (think Internet Archive meets the DVD-R :-) which one might subscribe to. That would be pretty cool.