I beta tested this tool before it was officially released, and I felt 25 URLs per campaign was too low. In the end though, even after going through a couple weeks of logs and tracking ROI, I ended up not needing more than the 25.
But many advertisers do not want their ads showing on any scraper site period, so having the increased 500 URL limit will make it easier for advertisers. Rather than having to "pick and choose" which would make the "top 25" list of URLs to block, I would bet most advertisers won't take the time or effort to find 500 content network site URLs to filter out.
I was a little disappointed to see that you still cannot block URLs from all campaigns at once. If you have a site you don't want any of your ads showing on, you need to add that site manually to every campaign.
You won't be able to access the tool unless you are opted into the content network.
More about the site exclusion tool:
[adwords.google.com...]
would'nt it be alot easier to add the 2 or 3 domains of the top content sites that I want to advertise on to an include list and not have to worry about it any further?
They do have the site targeting feature, where you can do just that, but it is on a CPM basis rather than CPC.
[adwords.google.com...]