By way of a thread at WebmasterWorld named API-Quotas, where members saw a drastic drop in the quotas they have for their API calls. It turned out the reduction of API queries was a bug and has been fixed since it occurred. However, before confirming that it was a bug, the rumors were that they pulled back the query limits for the AdWords API due to a new program that is suppose to be released named "AdWords Commercial Developer Program". Chris Sherman blogged about this in September but now it is January 2006 and we have no word from Google on it yet.
If you look at the FAQs page it says; "On January 1, 2006, we will launch the new AdWords Commercial Developer Program." And continues, "Starting in early December, a link to a registration page will be posted to the API home page and blog for those who wish to enroll in the program."
But there is no link to a registration page and its way after December.
If you noticed a reduction in your AdWords API calls or if you want to complain that the commercial developer program registration page is not live, shot over to WebmasterWorld.