If you buy old/used books...

Absolutely.

I actually bought a used book once and found a note tucked inside that read:

Dear Reader,

I am the one who donated this book to the secondhand store you bought it from. My name is _______ and I am a paraplegic woman in ______ who loved this book and would like to possibly exchange letters with you after you read it. If you would be interested in this, my address is _________ (it was of course a P.O. box). Enjoy the read!

It was really sweet and endearing and I would definitely have written her had I read the book. But I never got around to reading it and I lost it during a move. 😔

I voted yes because I always get curious where people are and stuff about them.

I did.
The letter was returned, addressee unknown. 😐

I bought a copy of The Hobbit at a school book sale. There was something written by Aunt somebody to the original owner. I though a few times about who they might be.

No. I bought a book for £20 a few years ago and now it sells for £7000.

{@chipmunkernie] 😆 that is if the hand writing is still legible

I typically just rip that page out or throw the book away and buy a fresher copy

Yes

Of course yes

The evangelicals love putting tracts in random books. That is permission to mess with them.