Why do mixtapes have dj shouting over the song all the time?

[ncnavguy]

Yeah I know, you'll be listening and in the middle of the song it'll be all echoed out like: YOOOOOOOOOOOOOO!!!! THIS IS DJ BLAH BLAZZO HOT CLUB 99.0 ... then it'll happen again with the dj saying the artist's name like twice in the song. But some mix tapes are still hot, even with yelling dj's