During the mid nineties, the UK had a limited debate on what the government should do to celebrate the new millennium. In the end, the government of the day (Conservatives under John Major) and taken forward by Labour under Tony Blair decided to construct a big tent in the middle of London: the Millennium Dome. I was not impressed (and my poor friends have had to put up with me whinging about it for over a decade now). You see, I wanted another project which I was convinced would mark the new millennium, set up research for the next century and allow the UK to give something to the whole world. That idea was to digitize the British Library and make it available to all over the Internet. I thought that such a database, coupled with a good search engine and APIs would be perfect for research, would be ripe for data mining, and just good fun to browse.
It's in beta at the moment and isn't perfect (e.g. the pages are not selectable text), but it shows what can be done. Most of the searches I've done have all resulted in the option to download the entire book (unlike Google Book Search, Microsoft are only using out-of-copyright books or books whose publishers have granted them the rights to publish). For example, I searched for the term astrophysics and found this book The Riddle of the Universe which has a link to download the entire book.
One interesting thing in the pipeline, according to Danielle Tiedt, the general manager of Live Search Selection for Microsoft, is full integration with web content (via Windows Live Search).