Officially, Javier Castaño is a 50-year-old shoeshine guy at a cafe in Malaga, Spain. But in his off hours, he serves as the secret guardian of some of Twitter’s most desirable geographic handles: @canada, @japan, @rome, @madrid — even, for a brief time, @NY. The story of how Castaño came to own (and later, not own) these high-profile accounts is almost as random and circuitous as Twitter itself.