Back in 1983 (eek!), Yellow Pages had a famous advert in the UK featuring the attempts of one (fictional) JR Hartley to locate a copy of his own out-of-print book, Fly Fishing.
So popular was it that someone actually ended up writing Fly Fishing by JR Hartley.
Well, Yellow Pages, nearly 30 years on, has released an updated version for the iPhone generation. I'm not sure it works unless you know about the original, but it's lovely once you do.