I noticed a couple weeks ago that my Google Chrome all of a sudden started displaying double lines under certain words in a lot of websites that I visit. Here is what you need to know to fix this problem:
1) There are at least two different types of technology used for this new type of text advertising:
There might be more, but these are all that I'm aware of. How you tell which one is showing in your browser is to just hover your mouse over any of the text that are underlined & are orange (or similar) in color.

Double line under text

Easy Inline Popup Box
Both will show you a popup ad, but if it says Easy Inline, go to step #2. If it says Infolinks, that means the website has started using pay per click advertising from a company called, you guessed it, Infolinks. This is site specific, meaning you have nothing to worry about because certain (mostly lame) websites decided to monetize using their (I think stupid) technology and your browsers are just fine.
2) For Google Chrome, Easy Inline is actually an extension called Fast Save (and probably something similar in Microsoft Internet Explorer & Mozilla Firefox). It's not a virus or anything that will harm your computer, so don't worry too much. Here's how you get rid of it:

My problems disappeared immediately after refreshing the pages without having to close the browser, but YMMV. That's it!