I’ve tagged authors on social media before when talking about how much I recommend their books, or the positive impact their work has had on me etc etc, and have generally got responses (which surprised me the first couple times) saying, essentially, “Thanks that’s so nice to read.”

I think most creatives like to hear positive feedback on their work, and as long as your message is about their writing and not your perception of the author (or a Stan-style missive) they’re generally happy to receive it.