Short answers, pulled from the story.
Indie rock originated in the United Kingdom, United States and New Zealand in the early to mid-1980s. The earliest known use of the term appeared in a the 15th of January 1983 Billboard magazine article by writer Roman Kozak, titled "Despite Hard Times, Indie Rock Labels Survive", where he used it as shorthand for "independent rock" to describe successful independent record labels in New York.
C86 was a compilation cassette released by NME in the United Kingdom featuring groups including Primal Scream, the Pastels and the Wedding Present. Bob Stanley called it in 2006 "the beginning of indie music". The tape's name became a genre descriptor in its own right, with bands on the compilation finding varied outcomes: Primal Scream won the first-ever Mercury Prize in 1992 and the Wedding Present charted eighteen times in the UK Top 40.
The Buzzcocks self-released the Spiral Scratch EP on their own label New Hormones on the 29th of January 1977, a moment the BBC documentary Music for Misfits describes as pivotal to the development of indie rock. The EP printed the recording process details and pressing costs on the cover, effectively showing other bands how to produce and release their own music independently.
Bands from Dunedin, New Zealand, signed to Flying Nun Records, defined a sound marked by jangly, droning guitars and indistinct vocals that proved particularly influential on indie rock's sonic identity. The scene was marked by the Clean's 1981 debut single "Tally-Ho!" and the 1982 Dunedin Double EP featuring the Chills, Sneaky Feelings, the Verlaines and the Stones.
Landfill indie is a term coined by Andrew Harrison of the Word magazine to describe the wave of formulaic derivative indie rock acts that proliferated following the mainstream success of the Arctic Monkeys. A 2009 Guardian article by journalist Peter Robinson declared the movement dead, citing acts including the Wombats, Scouting For Girls and Joe Lean & the Jing Jang Jong.
"Mr. Brightside" by the Killers spent 260 non-consecutive weeks, or five years, on the UK Singles Chart as of April 2021, the most of any song. It charted on the UK Singles Chart in eleven of the thirteen years leading up to that point and was the UK's most streamed pre-2010 song until late 2018.