What a difference a letter makes. Columbians, er, Colombians are fed up with foreigners constantly misspelling their name. And it’s not just Paris Hilton who has goofed. Virgin Mobile, P.F. Chang’s, Lufthansa, Justin Bieber, Ozzy Osbourne — and Richard Nixon — have all made the same mistake. Now, tens of thousands of Colombians are fighting back with T-shirts and on social media in a campaign called “It’s Colombia, NOT Columbia.” The instant anyone goofs in the media, the volunteer spell-check police shame them on Facebook and Twitter. Word!