It would be overstating the case to claim That Girl was the TV equivalent of Betty Friedan. If anything, the success of the show (which ran for five seasons, from 1966 to 1971) had more to do with Thomas' stylish outfits and ebullient personality than her proto-feminism. If the greatness of a TV series can be measured by how much truth it sneaks past the network guardians, then That Girl can't claim a lot. Thomas' character was a rising actress in an apparently sexless long-term relationship with struggling writer Ted Bessell, and she spent most of the episodes in some kind of trouble related to an acting job, or trying to reassure her conservative father that her desire for independence wasn't meant to insult his values. Outside of having Thomas appearing on a Dating Game-like TV show, or accidentally taking a gig as a "cavegirl" at a "key club," That Girl's strongest connection to the events of its time was the gorgeous location footage of a still-glamorous New York City.
Still, it wouldn't be overstating the case to claim that the series' popularity cleared the way for more shows about strong single women, from Julia to The Mary Tyler Moore Show. And Thomas' performance shouldn't be discounted. She had one of the most expressive faces in the history of television, and she could make the idea of feminine free will seem non-threatening and even cute. (Whether "cute" was an appropriate way to frame women's lib remains debatable.) If nothing else, Thomas showed that feminism could be fashionable, right down to the angular mini-dresses that made her look like a floating geometric shape.
Key features: A significantly different original pilot, commentary by Thomas and series co-creator Bill Persky on select episodes, and the aforementioned Thomas interview.