The online retailer of books and just about everything else was awarded three new patents, covering its purchase circles, search and consumer reviews. While Amazon.com's patent police would go after Web publishers, not consumers, the review patent could put the kibosh on the social networking components of many search services.

Amazon.com's purchase circles can be based on everything from a hobby to an employer, or they can merely peep to see what's the hot book among Oracle employees. The patent covers methods of forming circles and marketing to them, for example, by showing one person looking at a book detail page and who else in the circle has bought that book.

The second patent covers a method of discovering and delivering as search results related products from multiple categories, such as books written by Steve Martin, as well as DVDs of movies in which he appeared.

The third patent is the real kicker. It covers methods for encouraging consumers to write reviews of items they've purchased by determining the optimal times to send them e-mails or reminders.