*Shadow* fascination

I, as much as anyone, understand the lure of a dark and mysterious title that hints at danger and intrigue, especially when dealing with a YA paranormal book. But this is starting to get a little ridiculous:

Shadowland by Alyson Noel

Shadowed Summer by Saundra Mitchell

Shadow of the Moon by Rachel Hawthorne

Radiant Shadows by Melissa Marr

Shadow Mirror by Richie Tankersley Cusick

Shadow by Jenny Moss

Anyone else seeing a pattern here?