Because these search engines don’t search exactly the same sites it’s important to compare the results when they do. This is a better way to understand their performance.
If you are looking for an inexpensive book hundreds of matches may be irrelevant. On the other hand valuable books are rarely available in large quantities and each search engine does a similarly effective job when the book is rare. With rare books the principal difference is in the sites they search, not the completeness of the searches and no one searches every site.
Both AddAll and UsedBookSearch provide 3 fields to do general searches on their primary screen: Author, Title and Keyword while BookFinder provides the same choices in its advanced search. Bookfinder also provides a “Classic Search Screen” option in its advance search that is a single continuous presentation of search results – a better choice than opening many files. In every case with each search engine, if you find an interesting copy you can go into the listing site and conduct the same search again to confirm a copy’s relative merit.
All the search engines are heavily dependent on ABE because they have something like 50% of all book listings in the world. All the other sites have an unduplicated additional 50%+ divided into a patchwork quilt of listings. Because many of the businesses and individuals who list do so on more than one site (some more than 5) the searches engines find a great many matches that are actually duplicates. To test this we evaluated all the results found when searching for “Life and Confessions of James Gilbert Jenkins: The Murderer of Eighteen Men (searched simply as “James Gilbert Jenkins”), Napa, 1864. Of the 7 copies found Abe had 6. Given that the total matches of the three search engines was 61, ABE look looks very concise and efficient. It is also the fastest.
The sites charge different fees and structure their sales in different ways and you can see this using search engines. Sites such as Alibris, Chapters.Indigo, and BiblioQuest sell the book themselves and pay the bookseller a percentage but most sites simply list the book, receive a listing fee and an occasional transaction fee. As well, sometimes the same book from the same dealer is offered for different prices on different sites. Without looking very hard you will see that there are price differences. With search engines we are still in the “wild west” stage.