Yahoo Japan is showing NO ads for some keywords
Yahoo Japan (who owns Overture Japan) is displaying NO ads with certain keywords. Such words include the following: gun, tobacco, gamble, cancer, quit smoking, Rogain, hair growing, dieting, esthetic, wrinkle removing, spots removing, cellulite, liposuction and plastic surgery. There may be more, but you get the idea.
A search for “casino” found four ads. Three of them refer to Las Vegas and one to US. There were no ads for online-casinos.
I tried to make one ad for “quit smoking” to see what happens. Almost at the end of the setup process, a message in red letters popped out, saying that my ads are not displayed. The message listed four possible causes, but none of them were applicable to my setup.
So Yahoo Japan is blocking certain keywords to be used in the PPC ads. If your products or services are related to these words, then you have to depend solely on organic ranking with Yahoo Japan. With Google, however, you still can run PPC ads with Adwords.