how do sites like www.gettextbooks.com get their price data? ie. http://www.gettextbooks.com/isbn/0071375252 is it scraped from each respective site?
Impossible to tell without insider knowledge but at such a scale you'd think they have a custom crawler indeed.
im thinking they use the API tools that some sites provide but only the big ones like amazon and ebay have them...
actually - does FROOGLE have an api - that could be another option if it exists... It seems like something Google would give freely to the world.