A citation is about the same thing it's always been, only now instead of giving you complex directions to a paper document in a library somewhere, I can give the directions straight to your web browser, and you don't have to leave your seat.
And now here you are, instead of reading my essay, on which I worked very hard, for weeks. Now, why did I do that--send you away before you'd even finished the first paragraph?
Please be nice to me and go back.