After my class read this book in high school, we wrote the author and he responded. How often does that happen in today’s schools?
Probably the most well known example is Neil Gaiman who is extremely active on tumblr, at least prior to Elon used to be extremely active on twitter, and would regularly drop into discussions of their works.
Other notable examples (albeit less active) off the top of my head include James S.A. Corey (Daniel Abraham and Ty Frank) and Andy Weir.