This Youtube feature is an addendum to Karaoke Manager designed to use YouTube as a backup when one doesn't find a song on your online catalog (songs you don't have in your computer or exist on KarFun) they're given the option of submitting a YouTube url or artist/song (the user is aware that the karaoke version of the song exists on Youtube). They simply click a button to submit to you the url or information on the song as demonstrated in the video below.
Keep in mind when you can use Youtube