I hadn't heard of this being a feature (quite a small one), but I thought it was really cool when it happened. I have my parents in my address book as separate entries. Yesterday, my mom called, and what appeared? It recognized two names in my address book with the same number and displayed both of them: "Mom or Dad." A minor convenience, but I thought it was very cool. Edit: I'd forgotten about another bit of info: it also recognized that both contacts had the same last name and displayed "John or Jane Doe" (names obviously changed to protect the innocent).