Slate observes:

"Since October, Apple has been collecting playlists from musicians and celebrities at its iTunes music store.  For Apple, of course, these celebrity playlists are another way to package their 99-cent songs.

...

The worst of the bunch are those celebrity playlists padded with the celebrity's own songs, epitomized by the queen of the craven playlist, Beyoncé Knowles.  Eight of the 14 songs on Beyoncé's playlist are performed by her thin-voiced sister, Solange, by her former bandmates in Destiny's Child, or by Beyoncé herself.  It's enough to make you grateful for the honesty of Barry Manilow, whose well-crafted and classy playlist features just one of his own songs—'because,' he notes, 'I am shamelessly promoting my new 2-CD set.'"

Rocktations is fairly confident that any random sampling of the songs featured on its site would result in a mix tape as varied and well balanced as Rocktations' users themselves.