Complex sentence: In October 2013, Rap Genius was one of fifty sites targeted with notices by the National Music Publishers Association for the unlicensed online publication of song lyrics; most of the sites that were targeted were ad-supported.
Split into simpler sentences: In October 2013, Rap Genius was one of fifty sites targeted with notices by the National Music Publishers Association for the unlicensed online publication of song lyrics. Unlike Genius, most of the sites that were targeted were ad-supported.