In Bloom was released by Nirvana in 1991 on the album Nevermind, written by Kurt Cobain, and later issued as a single in 1992. Decades later the song's opening riff found a second life online when Turkish YouTube creators began using short music clips to mark their abone ol, or subscribe, calls. Its loud, instantly identifiable grunge sound stood out from generic intro music, so the clip spread between channels, edits and soundboards as a ready made subscribe cue that viewers quickly learned to associate with that moment.