A completely ignorant computer question.

So, I've almost always run my getting to be, ancient, Dell XPS 430 64bit computer with two screens. So, I frequently will answer an email, or comment on a blog by opening the original blog on one screen and then opening the same blog on the other screen for purposes of answering said blog, or email.

So, I am wondering how it is possible to view the same URL twice on the same computer and have it not get terribly confused?