RG has seemingly generated a unique URL w/<title> for each line of each of each song listing. Google slurps these up and gives them prominent SERP rankings, though the links are all just doorways redirecting to the main song page. (Albeit, redirecting to an anchor at the lyric queried, with highlighting effect and annotation popup to boot. Pretty friendly UX.)
Eg. http://rapgenius.com/9208/Ice-cube-it-was-a-good-day/Today-i...
Thus one song with a remix or two might become 469 search results: https://www.google.com/search?q=And+if+I+hit+the+switch%2C+I...