Amazon (apart from having cool services such as EC2 and S3) is known for it's infamous patents. And the patent office in the US known for having idiots as employees. A great combination! After their "one click shopping" patent, now A9 (amazons's search engine) claims their fame by patenting a String at End of a URL. Prior what? Something Drupal does -in combination with some mod rewrite voodoo- for ages.

Amazon search subsidiary A9.com was awarded U.S. patent no. 7,287,042 for 'including a search string at the end of a URL without any special formatting.'

And it is new according to Amazon, because:

Description of the Related Art
...
Some search engine sites support the ability for a user to submit a search query by encoding the search string within a URL (Uniform Resource Locator). Typically, however, the user must encode the search string in the URL using special formatting that is inconvenient or unnatural for users to type. For example, in some cases, users must add a special string such as "query=" to indicate that a search is being requested, and/or must add special characters to the search string itself. As one example, the URL www.google.com/search?q=mars%20rover may be used to the search for "mars rover."

Now it is clear that Amazon doesn't get a way with this and the moment they would sue a Drupal site that can do this like Drupal.org the complete blogosphere and OSS community would be against Amazon making them the paria that SCO has become. Yet, there will be a time -I think within the next 20 month or so- that Drupal.org, Dries, the hosting party or the Drupal Association will get sued over a patent. That's why we -not just Drupal but the complete Open Source community- have to get organized and be prepared for such a slaughter. That's why there is work under way from Dries and the Association to be prepared. And you can help the association. By donating time or money. Please do!