I’ve made something, but I’m not too sure what it really is or if it’s of any use what-so-ever!
I started playing around with the “relationships” code (briefly mentioned here) to see what would happen if you selected multiple books and ranked the aggregated suggestions by frequency of appearance.
For example, here are 4 O’Reilly books that I’ve selected. The code pulls in the list of suggestions for each book, then (underneath the line) displays the books that appear in all 4 lists, followed by the ones that are only common to 3 lists, then 2, then those that only appear in one of the lists (with up to 100 being displayed in total).
So, in theory, if I’d picked up those 4 books and was looking for a couple more to borrow, then “PHP & MySQL Web Development” and “HTML & XHTML” should be safe bets.
You can click on any of the books above the line to remove it from the selection. If you click on “HTML” and “Web Based Applications” books to remove them, then you should be left with the “PHP” and “MySQL” books — in that case, a book on e-commerce becomes the first suggestion.
To start with a random book, use the following link and reload the page until you find one that interests you and that has several suggestions…
…then try adding one of the suggested books to the selection (by clicking on it) to see what the revised suggestions are.