Inquisitor, Dave Watanabe's search tool for Safari, was the cause of a recent debate regarding disclosure of affiliate links. In response to public criticism, Watanabe has released a new version that both marks sponsored links and even allows you to disable the affiliate links entirely. He offers his response in a recent blog post.
You'll notice an update to the download page as well, offering a statement regarding the affiliate links that Inquisitor (now, optionally) inserts into search results. I commend him for this response and I think a lot of people will be relieved that they won't need to give up one of the tools that makes Safari great, even if just on principle.