Rich snippet spam, we hardly knew thee. Check out the latest victim of Google's algorithm improvements and avoid making these major markup mistakes.
Like we've mentioned before, Google is only getting better and better at catching manipulative SEO tactics. It's leaving no stone unturned, and when Google finds these tactics in play, you can bet the penalty hammer is coming down.
The latest example is Google's recent crackdown on rich snippet spam. Google caught wind of websites adding the rich snippet markup to irrelevant pages or spam content to entice searchers into clicking their links. Using the reviews markup on a page with no reviews? Penalty. Adding an author markup to a homepage? Penalty. And marking up content that's invisible to users? Definitely a penalty. Whether it's deliberate spam or just a mistake, Google's officially started taking notice and taking action.
To get the full story, check out this article at Search Engine Watch. And to ensure you're using rich snippets in a Google-approved way, check out Google's rich snippet guidelines.