In 2009 I heard about VOCALOID, but I did not know UTAU yet. Since I was already interested in Speech Synthesis, I was reading the Festival manual. The manual mentioned Flinger which stands for Festival Singer. There was a forum, in which both UTAU and VOCALOID had been named in one post. Since there was no way for me to get a copy of VOCALOID, I started using UTAU instead. Later I found out that people started extending Flinger to support Japanese. Later I found out that at least two users of Flinger know about VOCALOID, and one of them says that they also knew about UTAU.