Here are some of the main challenges faced in adult ad monetization:

Social stigma: The adult entertainment industry still carries a social stigma in many societies. This stigma may deter potential advertisers, publishers, and partners from working with adult ad networks. It can also lead to negative public perception and obstruct business opportunities outside the adult sector.

Limited ad formats and placements: Adult ad networks typically have limited options for ad formats and placements compared to mainstream networks. This limitation can affect the effectiveness and creativity of ad campaigns, making it difficult for an advertiser to engage their target market in innovative ways.

Fraud: Adult ad networks are more vulnerable to fraud than mainstream networks. This is because the industry is often seen as a lucrative target for fraudsters. Fraud can manifest in a number of ways, including click fraud, impression fraud, and domain spoofing.

Regulation: The adult entertainment industry is heavily regulated in many countries. This can make it difficult for adult ad networks to operate and comply with all applicable laws and regulations.

Ad blockers: Ad blockers are becoming increasingly popular, and they can significantly impact the revenue of adult ads. Ad blockers are software applications that can be installed on a user's device to prevent ads from being displayed.