Ads : Google Policy ?

Quote from Google :

Site may not include:

Excessive profanity
Violence, racial intolerance, or advocate against any individual, group, or organization
Hacking/cracking content
Illicit drugs and drug paraphernalia
Pornography, adult, or mature content
Gambling or casino-related content
Excessive advertising
Any other content that promotes illegal activity or infringes on the legal rights of others
Pop-ups, pop-unders or exit windows that interfere with site navigation, obscure Google ads, change user preferences, or are for downloads. Other types of pop-ups, pop-unders, or exit windows may be allowed, provided that they do not exceed a combined total of 5 per user session
Excessive, repetitive, or irrelevant keywords in the content or code of web pages
Deceptive or manipulative content or construction to improve your site's search engine ranking, e.g., your site's PageRank
Incentives (monetary or point-based) to users or third-party beneficiaries for online activity including, but not limited to, clicking on ads or links, performing searches, surfing websites, reading emails, or completing surveys
Sales or promotion of certain weapons, such as firearms, ammunition, balisongs, butterfly knives, and brass knuckles
Sales or promotion of beer or hard alcohol
Sales or promotion of tobacco or tobacco-related products
Sales or promotion of prescription drugs
Sales or promotion of products that are replicas or imitations of designer goods