Well, it’s official – Tweet is now officially a word. John Simpson, Chief Editor of Oxford English Dictionary, added the word in the June update of the English language through an official announcement…
“The noun and verb tweet (in the social-networking sense) has just been added to the OED. This breaks at least one OED rule, namely that a new word needs to be current for 10 years before consideration for inclusion. But it seems to be catching on.”