The vast majority of pornstar fan clubs are ripoffs. You spend $25-$50 and all you get is a couple glossies and some generic "newsletter" on coloured paper. Whoop-dee-doo. Worst case scenario, you piss your money away and never get a response at all.
There are exceptions (Lisa Ann apparently treats her fans very well), but many (if not most) of the pornstar fan clubs are administered either by an agency or by the pornstar's lackeys. Back in the 90s I joined a couple pornstar fan clubs and for the most part they were disappointments. At best your membership will be for one year only and usually you only hear back initially and then never again. It's a cash grab. And don't expect your mail to be read by who you want it to be read by...