I've designed, hosted, admined fan sites for models in the past.
You have to know what you want to get out of it though. If you want some casual blog type site you can go it yourself, post when you feel like it, interact with fans that post there, even set up a forum for some light discussions.
I think a fan site is good for a model because I feel it humanizes her more, she's not just someone on the other side of a cam (where if you are on cam time is money) and on a fan site you can chat about things more of your own personal interests.
If you have a goal to supplement your income via the site that's a whole different ball of wax, you are making a business and you have to treat it as such. When I worked with models on these types of sites I'd do all the work and the only $ i'd get (if any) would be from joint advertising accts that the model & i would share revenue from. If you want people to return to your site you have to offer them something, and content is king. The more content the better. The problems I eventually ran into is even thought I was doing most of the work models would eventually fall into "but I don't wanna make another photo shoot/video today" and when they become less involved the site gets stale.
An affiliate program operates like this. Other people out there in the adult biz or with their own websites sign up with an affiliate company. For an example (even though mfc has no affiliate prog to speak of lets pretend it does) We'll call it "mfc cash". So you sign up with mfc cash & they supply you with a unique id embedded in a referral link. You post that underlying some porn pic on your website, hopefully people click on it. You have to hope that they visit the site, sign up and actually buy something (tokens etc) and then you get a % of what they purchased, usually starting at 20% and going upwards depending on how many sales you bring them.
If you wanted to operate your own affiliate program on your fan site you need to be well established and have massive content.