Juli Clover, MacRumors:

Our ‌FaceTime‌ guide outlines everything that’s new in the ‌FaceTime‌ app in ‌iOS 15‌ and iPadOS 15, and many of these features are also in macOS Monterey and can even be used in tvOS 15. We’ve also included detailed how tos and tutorials so you can dive right into ‌FaceTime‌ after upgrading.

Another useful post, one that yields fruit with just a scan. I appreciate posts like this with a narrow scope, simpler slices through the river of new features introduced in the WWDC keynote.