Those dotted lines you see or don’t see are technically called a “selection rectangle” and the reason they exists is in order to help the user. The dotted rectangle appears when the active text or image link has (focus). The dotted rectangle area remains as long as the focus is set on the link. For the most part the rectangle pretty much stays on the screen even if focus is moved from link to link such as tabbed navigation. In my opinion is looks funky when you have this clean design and every time you click, up pops this sweet dotted rectangle box. Well here is my solution.

Solution:
a:active { outline:none; }

Example Selection Rectangle: