Domainers have long put AdSense blocks on their parked domains, in an attempt to make some extra cash off the higher-traffic ones. This practice is technically against the AdSense terms of service, and isn’t really fair to the advertisers, but Google had not done anything about it. After all, they get a cut of the deal.

Now Google has made available, to all users of the AdSense network in North America (other continents to follow), AdSense for Domains, a “legitimate” way to monetize parked domains.

Many publishers have approached us looking for a way to monetize their domains, and today, we’re excited to announce the expansion of AdSense for domains. This product allows publishers to earn revenue through ads placed on undeveloped domains.

With AdSense for domains, users can find relevant information rather than see empty pages or “page not found” errors. Today we present ads, links, and search results on the pages, and may add other useful information in the future.

Google has set some policies as to what domains are acceptable. One part that seems a little restrictive:

If Google becomes aware of a domain name that contains a trademark (or typo), that domain will be removed from the AdSense for domains network.

So basically you can’t drop some ads on a domain such as great-tutorials-for-photoshop.com, because it contains the trademark “Photoshop?” Or what if you use the term “Monster?” Monster Cable insists that they own the word “Monster,” and sue any company with “Monster” in their name, regardless of industry. I don’t want to start another argument about U.S. copyright/trademark, but is that really necessary?

The service works by pointing your parked domain to Google’s servers. You can then pick some colors and enter some keywords for the ads.