We broke out the news of Mozilla being penalized by Google for user generated spam yesterday. The only thing that Google revealed was that it was a granular penalty. The latest addition to the news is that the penalty was on one specific page out of the 22 million pages that Mozilla has.
Here's what Matt Cutts said about the penalty:
"In this particular case, it was the url http://blog.mozilla.org/respindola/about/ that we took action on, and that was because it was so defaced with spam comments. I checked the URL this morning and it was over 12 megabytes (!) of spam from 21,169 different comments. When a page like that lands in our search results, it's the sort of thing that users complain to us about, so we are willing to take action."
12 megabytes of spam from 21,169 different comments is of course a lot of spam. The URL has now been cleaned up by the Mozilla team.
Have a look at the Google Webmaster Mozilla Google thread:Mozilla Penalty Impacted One Page Out of 22 Million; Reveals Google!,