Please answer the following question: I know that the answer to the question "What happened to indie bands?" is in "Since the mid-2000s, the mainstreaming of bands like Wilco and Feist have pushed indie rock into the adult contemporary conversation. In the early 2010s, indie musicians like Imagine Dragons, Mumford & Sons, Of Monsters & Men, The Lumineers and Ed Sheeran also had indie songs that crossed over to the adult contemporary charts.". Can you tell me what it is?
Answer:
mainstreaming