It's a rap genius annotation. If you click it with javascript enabled, an annotation will pop up on the right hand side. Looks like on the main site it's design

It's a rap genius annotation. If you click it with javascript enabled, an annotation will pop up on the right hand side. Looks like on the main site it's designed to degrade gracefully so it just navigates back to the article itself, but on the hosted site the urls aren't re-written correctly.