Cahr, you go to your profile, and at the bottom of the first 'info box', below About Me but greyed out and to the right, there should be a Goodreads address with your user name in it. This doesn't show up on all profiles though - I think it's only for those who've actually chosen user names (as opposed to just logging in with their FB accounts or the like), which you do in Account Settings.
My profile is linked in my sig, if anyone's interested!
I'm bumping this thread because it's important! :tug And also to notify people who might have notifications on (or who run here once strangers pop up on GR) that I'll send friend requests to everyone who's posted a link to their account and I recognise as current members because I want to follow and be inspired by what you all are reading, peeps. Do with it what you will!
Eliza, yes pretty much. You can add friends and see what they're reading, keep track of books you have read, want to read, and are currently reading. You can create custom bookshelves, i.e 'Romance' or 'Favorite Childhood Books, etc. The possibilities for this are endless.
And there's an annual reading challenge. You can set a number, and Goodreads tracks your progress. I set my challenge at 20 this year, and I've already read 25.