Michelle Trachtenberg

Michelle Trachtenberg was another young Nickelodeon star who got big in the '90s, thanks to The Adventures of Pete & Pete and Harriet the Spy. (She also appeared on an episode of Clarissa Explains It All.)
After playing Penny in the live-action Inspector Gadget movie, she spent the first three years of the aughts portraying Dawn Summers on Buffy the Vampire Slayer, later starring in 2004's EuroTrip and the 2006 Black Christmas remake and landing the recurring (and ultimately iconic) role of Georgina Sparks on Gossip Girl in 2008.
And yet you saw the headline and went through the entire list to get to the point on the page where you can add a snarky comment. Sad really.