This looks like a very useful command to have more control over the ads and URLs:
keyword ** 0.25 ** http://www.yoururl.com/xyz
This could be easily utilized to build keywords that link to a search result page such as:
php book ** 0.20 ** http://www.myurl.com/?search=php+book
I am going to play around with this a bit to try to buy cheap clicks for one of my online stores.