I am proposing that the site offers a premium account for paying members. The amount paid could be nominal. Maybe a $1 a month x (how many members and you got yourself a self sufficient website).
The perks that are included with a premium membership is a logo on the side of the avatar that states such. Premium members should be excluded from banners, ads, etc. (I have adblocker so doesn't matter to me) or atleast something that would scream "premier member" perks.
Regular "non paying" members will get to experience the website for free and nothing changes for them and they get the same exact privileges as before.