This article in Wired magazine has finally pushed me to stop linking to Amazon.com when I refer to books in my blog. Sure, it's nice to get a small credit once in a while for referrals (which I invariably use to buy gifts for people I know), but I'm simply not comfortable linking to Amazon any longer. Instead, I'm now going to link to isbn.nu, which provides a really cool price comparison service based on a book's ISBN number. An extra benefit is that URIs at isbn.nu are really easy to construct and remember (and, I hope, more stable): they are just http://isbn.nu/foo as opposed to those Amazon URLs of the form http://amazon.com/exec/obidos/ASIN/foo/ (which they probably won't change, but how do I know that, and what the heck is an ASIN anyway?). The structure of ISBN numbers has been standardized, as has a URN scheme for ISBNs, so I'm also going to follow Ben Meadowcroft's lead by including the 'cite' attribute whenever I quote at length from a book, where the value of that attribute will point to the URN for that book (i.e., "urn:isbn:isbn-number").
Standards good.