I never dogear my books, but I do underline quite liberally, and mark pages with post-it's. My first copy of the brick is quite a rainbow as I underlined every line I found wise, amusing or beautiful and marked every page that mentioned Les Amis *cough* My new copies on the other hand have so far escaped with the post-it treatment.
Oh, and I started rereading 'The Social Contract' today, post-it's in hand. There are two of them on every other page I've gone through so far, I think...
It's easier to be odd or crazy or insane than to hurt all the time.
Be who you are and say what you mean. Because those who mind don't matter and those who matter don't mind.
God is not dead, nor doth He sleep;
The wrong shall fail, the right prevail.