You probably wouldn't believe how much it costs to develop and maintain a site like this, which is why many others have tried and failed.
Hosting and maintenance alone come in at many thousands per year. Development of version 2 which has been going on for almost 2 years now will run into many tens of thousands before it's complete.
Obviously we have to cover our costs somehow and it's the paid members that keep this site going. Without them we'd fold overnight, so if you value this site and are benefiting from the many free features, you have them to thank.
The difference between this purpose-built site and off-the-shelf forums will hopefully be a lot more apparent when version 2 goes live. Without wanting to build it up too much (since there's bound to be initial teething problems), I think it will be quite a big improvement on what we currently have, especially for mobile users. Although it won't solve all our current problems, it will bring the site up-to-date, hopefully making it look and feel as modern as any other website out there. After the initial launch we'll continue to fix and improve, since FF development has always been an ongoing process.
As has been stated above, if you feel like contributing to the community by taking out an upgrade that's always very much appreciated. On the other hand if you just want to enjoy the free features and perhaps contribute with occasional pics or posts, you're very welcome to do so. Although FF is a registered business, this site is primarily a community and everyone is welcome