Another common use of borders is to highlight a paragraph or news item. We use it on this site when you see an info box with the addition of a background color to set it off even more. To refresh your memory:
This is an info box. It has a border, padding, margin as well as a backgound color.
If you examine the info box, you see that it has a border, but notice the space around the text? That is padding. Last but not least you'll notice that the info box is indented on both sides and has spacing above and below, that is margin.