I got this somewhat amusing email from Auction Ads:

We have noticed that your AuctionAds account is sending an extremely large number of dynamic keyword requests.  While it may seem like that method would provide the best experience for your users, and the best conversion, that is not the case.  Dynamic keywords put a strain on eBay, AuctionAds, and most importantly do not display those ads anyway because of the caching delay.

Please remove instances of dynamic keywords.  One method publishers have used is to create an array of common keyword searches on your site.  If a user enters a common term, that can be sent to AuctionAds.  Other, random keywords should default to a common popular item.   As a result of the strain on our network, further violations will result in your account being banned from the AuctionAds network.

We appreciate you as a publisher and hope you will see to fixing this issue.

Apparently they’re having some growth issues, and are sending this out to try and decrease load.  Something tells me their big publishers, regardless of usage, didn’t get this in their inboxen.