They're looking very carefully now. If your site is new or new designed and getting backlinks in a short time, your site goes to spam team's inbox, they take take a look at your site and take you down. I am not talking about scrabox and high pr'ed backlinks, just 100-200 backlinks from low and no pr blog posts. They should have increased their anti-spam team. A site of mine getting de-indexed manually yesterday, the de-index time looks like the team is from US.