Most businesses who operate websites and even mobile apps have what's called a "Terms of Service" contract that explicitly states the legal relationship between the company and the user. In most cases, the TOS will require users to engage in less-costly arbitration before filing a lawsuit, should a problem arise.
Eric Goldman, a professor of law at Santa Clara University School of Law, in California, blogged extensivly on this, and his analysis is an eye-opener for anyone who's running a website with a fast-and-loose TOS.
The upshot, per Goldman: Judges would rather see websites explicitly confirm with users that they have had a chance to see the TOS, rather than just putting it in small print at the bottom of a website.
Technically, this is no big deal to implement within a website's architecture -- dead simple, in fact. But wow: Zappos is now in a world of hurt, as a poorly implemented TOS has increased its legal exposure significantly, as Goldman notes.