As of today, Amazon.com has a new search feature, so you can find books "based on every word inside them."
It sounds promising, but the system has a few shortcomings:
Search results include only books for which Amazon.com has the publisher's permission to display copyrighted material. It took me a while to figure this one out, after plugging in some odd words I've come across in recently read books and not getting relevant results. Although they claim that 120 000 books are searchable in this manner, there are many, many more books in the world.
Results cannot be sorted in a particularly useful manner. Of course, that's not a problem with the search mechanism so much as with the preexisting sorting feature. An alphabetical sorting does not let you skip ahead to entries starting with, say, "J" — you have to get there by clicking "Next," "Next," Next"...
I don't know about you, but I'd be likely to want to use this sort of feature in this way: "'Rocket experiments' — what was that book I heard Steve talking about? There were a lot of rocket experiments. And it was a mystery book for kids." I search for "rocket experiments" but can't refine my results by category.
It clutters up traditional book searches. There's currently no way to specify whether you would like to include a text search, or stick to titles and key words. A search now results in so many titles as to effectively supply no results at all.
The new search feature is not available at Amazon.ca. I wonder if that has to do with copyright laws.
On the up side, the system is smart enough to not accept "the" as a viable search term.