It is technically a registered business (an LLC), not private property, and the terms of service can be viewed as a contract, so contract laws apply if someone really wants to go there. (not saying they should). The TOS is a mutual agreement and money given to the site technically isn't a donation as this is a business, not a charity, but a voluntary membership fee.
I'll try to respond to both of your posts here. Please note that IANAL, I do not play one on TV, and I didn't stay at a Holiday Inn Express last night. :wink:
Not-for-profit is an actual legal designation by the IRS for tax-exempt activities. No, FR is not a tax-exempt activity. Yes, FR is an LLC. Yes, FR is private property, specifically intangible personal property. (i.e. an asset that can be acquired or used for collateral) State laws vary, but in general, a business can accept donations or sponsorships.
Members of FR must register to post comments at FR and, in doing so, agree to abide by the User Agreement . As you said, donations are voluntary. Donations are not required to be a member of FR and the acceptance of donations doesn't come with a guaranteed right-of-access to or use of FR. If I remember correctly, even the User Agreement stipulates that JR can change the agreement without notice.
Since, IANAL, I won't touch the subject of contract law with respect to FR's User Agreement or refunds due from termination of an agreement. My layman's understanding is that a donation is not a purchase of a service or good.
I do know (from friends' statements and not evidence I've seen) that JR has offered and given refunds and cancelled voluntary donations from freepers who seem particularly unhappy even though they didn't request a cancellation. I am a monthly donor to FR and have been for years. I have gotten sideways with JR a couple of times and asked that my donations be cancelled. He always obliges without hesitation.
All of that said, my original assertion stands. FR is private property and, as the owner, JR can refuse to grant membership, revoke membership, and change the site's User Agreement.