Friday afternoon Google launched a new interactive page to show how its search works, just a lot of stats and a breakdown of the basic process.
But there's one link on that page that is actually super valuable to us in adult. This page shows around 50 examples of pages Google has deindexed for spam in the last hour:
http://www.google.com/insidesearch/h...ting-spam.html
You can click through it and see real exaxmples of pages they found spammy enough to penalize. They of course don't tell you why they considered them spammy, but you can research the URLs to find out and compare what they did with what you're doing to make sure you don't raise the same flags.
This graph from that same page shows monthly penalties by type of spam.
Of all of the sites I've reviewed for clients I've found these to be the most common in adult:
Unnatural links from your site (link trading)
Thin content with little or no added value (model bio pages)
Unnatural links to your site (link trading and lazy link building)
Hidden text and/or keyword stuffing (common on tubes, dating and cams)
User-generated spam (blog comments)
Good stuff to know so you can be sure to steer clear of the mostly commonly hit techniques.