WASHINGTON — For a spy agency that likes to operate undercover, the CIA's debut on Twitter has revealed a cryptic sense of humor.In a medium heralded for its snide remarks, the Twittersphere gave high praise for the intelligence agency's first tweet, under the handle @CIA.It debuted Friday with a sly message neither confirming or denying it was the CIA's first tweet.Within an hour it had gained more than 67,000 followers.The agency quickly confirmed in a news release that it had, in fact, established a presence on Twitter and also on Facebook.Its Twitter page described the CIA as accomplishing what others cannot accomplish and going where others cannot go.On both accounts, the CIA promised photos, reflections on intelligence history, and fun facts from the CIA World Factbook.