Yui Hirasawa is the lead guitarist and vocalist in K-On, the Kyoto Animation series from 2009 adapted from Kakifly's manga about a high school light music club. Her excitable greetings became a signature part of her character, shared by fans as short clips on forums, videos and soundboards. This Yahooo call was cut down to a standalone reaction sound, similar in use to tuturu, and it stayed popular because it captures Yui's carefree personality in a single second that anime fans recognise without any context or setup.