That's the URL of the link. The normal ads are just fine but these ones pop up as little floating banners always on the bottom of the screen. Slows down all the scrolling and interferes with forward/backward finger gestures.
Browsing normal site on iPhone 5 with iOS 7.1.1.
Another. Not related to any of the usual banner ads on the top or sides.
Seems to be unique to browsing on a mobile device.
Also tends to disappear on moving the page. And then reappear when you stop moving the page. Sometimes right in the way of what you happened to stop moving to read or click on.
Edited, May 22nd 2014 6:18pm by TirithRR