One of my wallpaper site with 2k visitors/day got de-index. I don't know why it happed. But I got email from google webmaster that my site is PURE SPAM and make changes and then re-apply. This is bullshit from google that they didn't pin-point where exactly is the problem. Its so pathetic.
It would be great if any one can tell me what pure spam they mean. My site is a wallpaper site and no affiliate or article based site which copied data from other sites.