Google has been getting a lot of flack lately, especially surrounding its core search product, but that doesn't mean that all it's been doing lately is try to shove Google+ in your face as much as possible.
One very interesting option seems to have been rolled out recently, the ability to block ads from a particular domain, very similar to the ability to block domains that you don't find helpful from the search results.
This is how it works, if you click on an ad link and find that it's not really what you're looking for and hit the back button in your browser, you will see a link to block all the ads from that particular domain.
Presumably, this works just like the search results feature works, meaning that the block is cookie-based. This means two things, one, it works for signed-in and signed-out users alike; two, the block doesn't transfer to your other computers or your phone for that matter, even if you're signed-in.
Still, it's a great option, perhaps even better suited to ads. Google introduced the ability to block domains from the search results last year.
Domains that users added to their blacklists would not be part of any future search results, though users did get a notification saying that there are blocked results.
A while after the feature was introduced, Google even started using it to check whether its set of Panda updates, which focused on poor quality sites, demoted sites that users had blocked in mass. The data was also used for ranking.
Now it has the option of doing the same for ads, which it also ranks according to a number of criteria. What's more, advertisers don't really have an option than to play by Google's rules, so the company can use the new data to force advertisers to improve their content, or try harder to elude Google.