Derives from the French "coucou" (cuckoo), which is normally used for greeting in a friendly yet old-fashioned way. Young people have been re-using it, changing it to "kikoo", which sounds even friendlier, and maybe cuter. Teenagers overuse it on communication devices, like MSN, text messages, message boards or blogs. Over time, it has become a way to detect stupid people or just young people (often the two) among the rest of the normal population. Kikoo is a synonym of being less than 14. And stupid.
by EKClow May 23, 2008