Many years ago, my then-8-year-old friend Spencer asked a prominent jazz musician for an autograph, but when he was given the usual signature, he scolded, "Not your name... Mine!" Following his lead, I've been asking writers, artists, politicians, and actors—from artist Yoko Ono to filmmaker Wim Wenders, Black Flag frontman Henry Rollins to Dan Castellaneta (the voice of Homer Simpson)—to sign my John Hancock, er, Paul Schmelzer. So far more than 70 have agreed...Visit signifiersigned.com to see who signed and who didn't.