Mozilla.org, the non-profit organization behind Firefox, Thunderbird and tons of developer oriented tools, was penalized by Google.
Christopher More, Mozilla's Web Production Manager, posted the details of the penalty in the Google Webmaster Help forums. You'd think Mozilla, an organization that is/was mostly funded by Google, would have other means to get the issue resolved.
The penalty was a "manual penalty" due to extremely spammy user generated content. The penalty notification read:
Google has detected user-generated spam on your site. Typically, this kind of spam is found on forum pages, guestbook pages, or in user profiles.
As a result, Google has applied a manual spam action to your site.
So where is this spam? John Mueller of Google responded showing him. Just do a site command search for [site:mozilla.org cheap payday seo] and you will find some samples. It seems to be coming from spammers abusing the blog comments and the addons section, amongst others.
This is a case of Mozilla allowing anyone to come into their home and make a mess and not clean it up - it happens all too often and it is sad to see.
John offers some advice, for the comments, you need a spam filter and someone to monitor them. For the add-ons section, John said:
For these kinds of sites, it may make sense to allow the community to help with comment moderation (eg. allow them to flag or vote-down spam), and to use the rel=nofollow link microformat to let search engines know that you don't endorse the links in those unmoderated comments.
John also added that in these cases, Google tries to go as "granular as possible with our manual actions." So in this case, Mozilla is not fully penalized, just the sections or pages that have this spam on it.
Forum discussion at Google Webmaster Help.
Update: We have an update to this story at Google To Mozilla: You Had 12 Megabytes Of User Generated Spam On One Page.