The Google AdWords blog reports that Google has removed the cap on the number of sites an advertiser can remove their ad from in the Site Exclusion Tool
Today, we'd like to let you know about a recent change: you can now exclude an unlimited number of sites. We hope you'll use the Site Exclusion tool to improve your ROI and refine your targeting across the network. And, as always, we'd like to remind you that excluding a site (or a section of a site) from one of your campaigns will prevent your ad from showing on all of the pages of that site (or section). Therefore, to ensure you don't miss out on any potential customers, we suggest that you review a site carefully before deciding to exclude it from your campaign.
This will enable the advertisers who opt in to Adsense to remove their ads from the sites they do not wish their advertisements to appear upon. The limit posed in the Site Exclusion List has been removed.