[Cthulhu_]

There's non-destructive ways to do so; take a photo, post a review, write a blog post. Actually Facebook and Instagram are known platforms to "leave a trace" like that, its shady side aside.

But also, plenty of public places like museums, restaurants - at least where I live - have a "guest book" where you can leave a message. I like to believe other visitors and the staff have a leaf through those every once in a while.

[Retr0id]

Guest books are neat, but it's rare for someone maintain a guest book for the underside of a road bridge for example (with some geocaches being an exception!)