The Chordata RSS and Atom newsfeed directory is offering a 90 page eBook (PDF) on search engine optimization to anyone who rates 25 feeds by November 21. You’ll need to create an account and log in to rate feeds. Once you’ve rated 25, you’ll find a link to the eBook on the My Account page. At present, only about 5 or 6 percent of the feeds listed in the directory have been rated, and most of those only have one vote. The promo is aimed at getting the majority of the feeds rated by multiple reviewers.