What are Themed Ad Units. Simple. They are ads that have special colors and graphics to celebrate the season! For instance, you might see your ad with orange print with a picture of a black cat for Halloween. How about red print with a green mistletoe for Christmas?
The Themed Ad Units are specifically tailored to users in the appropriate locations as determined by their IP address. For instance, a user in the United States might see colors and graphics appropriate to the Fourth of July while users everywhere could see colors and graphics for New Years Day.
Again, it’s your choice and your page. You can turn Themed Ad Units on or off by yourself. Just log in to your account, go to the My Account tab. On the Account Settings page, scroll down to the Ad Type Preferences section and click Edit. You can now enable or disable the Themed Ad Units. Click save changes and Voila! Your selection will apply to all your Google Adsense Ads.