The sitcom that by now is almost a synonym for classic got that way by doing all the things that everyone at the time knew you weren't supposed to do. You couldn't have a female star who was both attractive and funny. You couldn't have her male lead be an urban Latino whose Cuban accent was thicker than a platter of ropa vieja. You couldn't build a story line around a (gasp!) pregnancy. Lucille Ball's contributions to TV's past are so obvious--Vitameatavegamin, the Tropicana Club, the slapstick routines--that it's better to note what this show says about today's future: sometimes the greatest sign of a future classic TV show is that it doesn't look like classic TV.
The other shows that made the top 17 are; The Ernie Kovacs Show, The Super Bowl, Seasame Street, The Mary Tyler Moore Show, MASH, An American Family, Hill Street Blues, MTV, The Cosby Show, The Simpons, Twin Peaks, Beavis and Butt-Head, The Sopranos, Survivor, 24, and Lost.
Check out the rest of Time's Top 100.
Personally I think they should add "The Lucy Show" as well as "The Carol Burnett Show", "Lost in Space" and "Rosanne" but then I don't compile the list!