A WebmasterWorld thread has Google AdSense publishers asking for a wild card feature in the Competitive Ad Filter panel.
In short, some publishers would like to block any ad that is pointing to a .info TLD from displaying on their sites. Why? Well, a nice number of those sites are made as throwaway domains and provide very little extra value. I am not saying all .info TLDs are like that, but many are.
Right now, in the Competitive Ad Filter panel you can block by domain, page, directory or subdomain but not using a wild card operator to block TLDs or URL patterns.
example.com: block all ads across all subdomains
sports.example.com: block only ads across the 'sports' subdomain
sports.example.com/widgets: block all ads below a specific directory
sports.example.com/index.html: block all ads for a specific page
Forum discussion WebmasterWorld.