I read this thread, and although it is older, I felt compelled to offer our personal experience with the company.
Yes, they are fairly new, & far from scammers or con artists. Many online businesses offer an incentive for referals. This enables them to grow quickly. If you use a company and are pleased, word of mouth can often be the best advertisement, and it multiplies their base of consumers. Referrals from pleased consumers is free and saves tremendously on the high margin of advertising costs.
We bought this membership last summer and are quite pleased. A few of the sites are $5.+ more than the advertised fee, but nothing huge in cost. These guides can be offered to the buyer at a tremendously low price, due to the fact that you are NOT shipped the actual books. You receive a link and password, and a plastic card with your name, etc., and a # on it to present to the park you will be using.
It has been extremely helpful to us, due to the fact that these are listed, state by state and city by city after YOU print them out. Included are phone #'s for the park, address, and hours of operation + costs and brief guidelines.
It is legitimate I feel, and NOT a scheme, so do not hesitate if you could use info on parks. We found it a lot easier to look up a particular state and locate availability, BEFORE we leave home. (This 'ole gal is too old to be a gypsy )!
I hope this helped someONE ! That was my only goal. God bless you !