This weekend, Google issued a manual action on Thumbtack, a Google Capital backed company, for unnatural links pointing to their web site.
I received confirmation of the penalty earlier this week from their co-founder, Jonathan Swanson.
In short, Thumbtack gave businesses "progress points" for verifying their web sites by placing a link with very keyword rich anchor text on their sites pointing back to the Thumbtack web site. This is what led Thumbtack into a manual action.
Last night, Thumbtack sent an email to all the businesses that have these verified links asking them to either remove the link or add a nofollow attribute to the link.
The email said that they are making this change because their original policy was "against Google's policies," admitting they "messed up" and should not have "given incentives for linking."
Here is a copy of the email sent to me via @NortheasternExt:
Even a Google funded company needs to be careful. I suspect they will come out of the manual action real soon after sending this email to their businesses.
Forum discussion at @NortheasternExt.
Update: Less than a week later, the penalty was revoked.