Thanks for link. But the selection seemed very odd. I wondered how they got that list from HN. The site says All links to Amazon, Safaribooks and O'Reilly get

Thanks for link. But the selection seemed very odd. I wondered how they got that list from HN. The site says All links to Amazon, Safaribooks and O'Reilly get extracted once a week from Hacker News posts, make sure they are indeed books and then rank them based on how often they are mentioned and the karma of the user. Ahh. I guess that's it - people don't bother giving Amazon/other links for well-known books. Or sometimes the book has its own website. Also, that site makes money by linking to Amazon. That seems a bit dodgy to me! Hmm is it really that hard to extract book titles that aren't links to Amazon/publishers? C'mon hackers! :-)