You may see some words or phrases with a double underline.
These links are part of a pay per click advertising program called Infolinks. Infolinks is an In Text advertising service: they take my text and create links within it. If you hover with your mouse over these double underlined links, you will see a small dialog box containing advertisement related to the text marked. You can choose to either move the mouse away and go on with your browsing, or to press on the box and go to the ad page which is relevant to the text.