I'm reminded of Mitch Hedberg's bit about getting a receipt when buying a donut. "I don't need a receipt for the donut. I'll just give you the money, and you give me the doughnut. End of transaction!"
Why do we need massive TOS for stuff? I'll just give you the money, and you give me the service. End of transaction!
Presumably because an ongoing service isn't a clean exchange of physical goods. It's more analogous to a gym membership which definitely does come with a contract.
By eating this donut you agree that we are not responsible for any health problems that might result, either directly or indirectly.