Countless independent acts in every genre — punk, hip-hop, church choir — relied on him to create small runs of high-quality records and CDs.

The streets of New York are a backdrop for countless TikTok and Instagram videos.

© Amir Hamja for The New York Times

Unlike celebrity influencers with large followings, these creators produce a blizzard of videos for a fraction of the cost of traditional online campaigns and, in the process, shift public conversation.

© The New York Times