Facebook (FB) may have plans to introduce a monthly subscription fee option that gives users more features on the world’s largest social networking site. A patent application titled “Paid Profile Personalization” describes how the company could “replace advertisements or other elements that are normally displayed to visitors of the user’s profile page that are otherwise controlled by the social networking system.”

The small advertisement boxes that Facebook currently displays could be replaced with pictures of their significant other, a pet or even their favorite cars for those who pay a monthly fee. Paying members may also have the ability to rank their friends, display special status messages on their pages and have more freedom when messaging other users.

While most patents never see the light of day, Facebook has been under pressure from Wall Street to increase its revenue and further monetize its more than 1 billion monthly active users.

The patent notes that such a feature would “improve the overall user experience while maximizing revenue to the social networking system.”