As a digital and cultural phenomenon, the realm of online social media is still in its infancy. But as a legal matter, social media is nearly in its 30s, according to the outline of “Key Moments in Social Media Law,” compiled by John Delaney for AmLaw 100 firm Morrison & Foerster’s Socially Aware blog.

For many users of contemporary social media, the Social Year Zero would probably be 2002, when Friendster first appeared online and posited the use “friend” as a verb. But MoFo’s Delaney starts the social legal clock on January 17, 1984, when the U.S. Supreme Court handed down its decision in Sony Corp. of America v. Universal City Studios, Inc.:

. . . finding that Sony was shielded from copyright liability arising from infringing uses of its Betamax video recording device. . . This decision has allowed device manufacturers and service providers to flourish in the digital era. Perhaps the most important technology law case in this country’s history.

After that, the timeline jumps to February 1996 and the passage of the Communications Decency Act into U.S. law. According to Delaney, the law established “a safe harbor that provides broad (but not unlimited) protection for interactive service providers from liability arising from information posted by a third party.” The law, in essence, allowed blogs and other contributor-driven online media—up to and including sites like Twitter and Posterous today—to thrive, as they were protected from being “routinely run out of business by defamation lawsuits arising from user-posted comments, no matter how outrageous those comments may be.”

From there, the MoFo list picks up speed, noting two key legal milestones in 1998—the U.S. Court of Appeals allowing companies to patent business methods, and the passage of the Digital Millennium Copyright Act—before diving into the digital-media-saturated new century with important cases about file swapping (MGM Studios v. Grokster, in 2005), ownership of copyright when posting materials online (MySpace’s clash with singer-songwriter Billy Bragg in 2006), and the provenance of Facebook (the opening salvo in 2008 of the Winklevoss twins’ battle with Mark Zuckerberg, and Paul Ceglia’s 2010 suit claiming 84% ownership of the now-massive social media hub).

All told, Delaney identifies 20 pivotal legal moments in the social media sphere, ending in 2011 with the May 19 IPO of Linked In—which he calls “the first major U.S. social media site to be publically traded”—and Facebook’s November 29 settlement with the Federal Trade Commission over its user-privacy policies.

As social media services become increasingly pervasive in the corporate and personal spheres—and as online behemoths like Google, Facebook, Apple, and others continue to battle over the social space—the MoFo “Key Moments in Social Media Law” list reads like an early first draft of a history that is bound to become a bit more complicated and a lot more litigious.