I used to do that, but since I mostly read on public transport and I'm always on the go, I stopped doing it.
I think you've inspired me to always carry a pen with me ( ´ ▽ ` )b

At first I thought the same thing, but if you think about it, it's like giving the book a little bit of your essence, as if you had actually read it yourself, I don't know, that's just how I see it. (─‿‿─)

i don't usually do that, but i've been considering annotating my fav pages and chapters lately!
also, is it a specific group?? i'd like to join it :)