YouTube has landed a veteran ad agency executive as its new vice president of brand, media and experiences. Tom Blessington is departing Portland ad agency Wieden+Kennedy, where he's been since 1990 and currently serves as managing director, to join Alphabet Inc.'s San Bruno-based YouTube division. Reporting to YouTube Chief Marketing Officer Danielle Tiedt, he'll lead the video platform's brand strategy and integrated marketing campaigns. “Tom is well known for his culture-shaping, innovative…