You must follow certain formatting rules when specifying the domains you want to block.
Domain blocking is specific to the exact domain address you enter. For example, blocking example.com has a different effect than blocking www.example.com. Keep this in mind as you enter domain addresses so that you block the domains you really intend to block. The following examples show you how domains are blocked, based on the domain, sub-domain, and directories you specify.
example.com
Notice that this example does not have "www." or any sub-domain. Entering example.com would block everything using the example.com domain. This means your ads would not appear on pages under such domains as example.com, www.example.com, www1.example.com, taxes.example.com, or www.example.com/news. You should use the format in this example (without "www." or any sub-domain) if you want to block the entire web site.
www.example.com or services.example.com
These examples would block the specific sub-domain. So if you blocked www.example.com, your ads would not appear on pages under such domains as www.example.com or www.example.com/prices. But they could appear on pages under such domains as example.com or reservations.example.com. Likewise, if you blocked services.example.com, your ads would not appear on pages under such domains as services.example.com or services.example.com/massage. But they could appear on pages under such domains as example.com or www.example.com.
Keep in mind when blocking sub-domains that you cannot have more than one sub-domain in the address. For example, you can have services.example.com (which has one sub-domain, "services"), but you cannot have massage.services.example.com (which has two sub-domains).
www.example.com/news
This example would block the specific directory. So if you blocked www.example.com/news, your ads would not appear on pages under such domains as www.example.com/news or www.example.com/news/money. But they could appear on pages under such domains as www.example.com/faqs, www1.example.com/tips, or taxes.example.com/news (notice the different sub-domain "taxes" in this last example).
Keep in mind when blocking directories that you cannot have more than two directories in the domain. For example, you can have www.example.com/news/money (which has two directories, "news" and "money"), but you cannot have www.example.com/news/money/rates (which has three directories).
The domain cannot be more than 500 characters long.
The domain cannot contain any of the following characters: "?" "&" ":" ";"
It does not matter if you enter the protocol (for example, the http://) since we remove that part of the domain automatically.
You cannot block more than 250 domains at the account level.
You cannot block a Yahoo! domain.
You cannot block a top-level domain (for example, the domain extension .com). The highest level you can block is a root domain (for example, example.com).
To learn more about blocking domains, see: