This sound is widely recognized in Japan as the “hee” reaction associated with trivia-style television. It became popular online because its delivery is so short and specific: not a scream, not applause, just a compact note of interest. That makes it easy to drop into meme edits, fact videos, and reaction posts where a creator wants a clever or understated response. Its staying power comes from how flexible it is across formats, especially when a clip needs something drier than the louder WOW (MLG) style reaction.