Here's a f'rinstance. Today Amazon sent me a friendly note, recommending this book, by W. Leon Smith and everyone's favourite crazy woman, Cindy Sheehan. Why on earth did Amazon think I'd be interested? Because "We've noticed that customers who have purchased You Can't Say That! : The Growing Threat to Civil Liberties from Antidiscrimination Laws, by David E. Bernstein, also purchased books by W. Leon Smith". Now I've never heard of this W. Leon Smith fellow, but if he's co-writing books with Mother Cindy, then I don't think I'm interested in anything else he's written either, even if the people who buy them are also discriminating enough to buy Bernstein's book.