Google has in the past penalized it’s own properties five times for breaking its own SEO rules. Matt Cutts has apparently now also sanctioned Google Plus with a manual penalty. Here are the comments from the internal email that was forwarded to me:

“Forks or no forks, we believe that the Plus team has overdone their link building. Starting at 9 am tomorrow we have manually applied a penalty to the subdomain. This problem first came to light when an engineer working the PR Toolbar noticed that the Plus sub domain had achieved a page rank of 11. We decided we either had to act or change the algorithm. Neither choice was appealing but the manual penalty seemed the more appropriate path”.

He went on to say that:

“[there] are a number of violations of our linking policies that we have repeatedly pointed out to the team but its seems that we have been ignored. They include but are not limited to:

Rel Publisher – we have long ago deprecated header links in our algo but the Plus team was insistent on pushing them into the market place at such scale that they were impacting ranking.

Rel Author – We absolutely can not allow the quid pro quo of a photo that increases click throughs in return for a link. It’s not a paid link but it effectively is pay to play even if it has generated significant traffic for Plus.

In-Post Do follow Links – while we recently no followed links from profiles, all of the links inside of Plus posts are still do-follow links. Given our current policy on guest blogging, we need to hold the same standard for Google Plus.”