It’s hard to see examples of FOSS being used widely between people. This could be the 2nd time after Mastodon that a FOSS project receives massive attention.
I can’t recall other software that the public might have used without knowing it’s open source. The ones I can get off the top of my head may be Firefox or Inkscape.
The Linux kernel in just about every Internet device. Most people don’t realize that.
Yup. Nearly everyone runs Linux. They just don’t know it.