I just searched for John Battelle's book The Search through Bookpedia, choosing amazon.co.jp as the site to search. The keywords I put in were "battelle search".
I got 4 results: Diet Revolution by Barry Sears; The Baby Book by William Sears; Tips for child raising by Martha and William Sears; and some book by Margaret King Sears.
If I do the same search in a browser at amazon.co.jp I get 4 results, and they're all different editions of the book The Search by John Battelle.
It's no great hardship to ignore Bookpedia's search function and search directly on Amazon Japan, but I wonder why Bookpedia's results are all books that don't contain any of the search terms. Are there any tips for better searching with Bookpedia?