Last month Google penalized MyBlogGuest, reminding people about the risks of guest blogging, and this time it is yet another guest blog network- PostJoint. Google's Head of Search Spam, Matt Cutts, confirmed the same as a response to a tweet saying “any link or guest blog network that claims to have zero footprints is waving a giant red flag.”
Google no longer shows PostJoint in the first page of the search results for a search made on their name, but what appears is only a poor quality AdWords ad. Just like what happened following the MyBlogGuest penalty, it is most likely that the link cleanup companies will soon hitt PostJoint. When Google penalized MyBlogGuest for similar reasons, PostJoint published a blog post saying how it is different than the former. They also claimed on their website that they had "no footprints."
PostJoint has confirmed the penalty in the comments section of the same blog post, saying it is a manual action penalty, not from any incoming links. Saleem Yaqub, Director at PostJoint added, “there are still no footprints and nobody can browse our complete site list. Any penalties received by our users are most likely due to an overall pattern of unnatural inbound / outbound links and participation in other platforms.”
PostJoint also pronounced on its website that they are "not a dodgy link network" and posted an article, reading "Will Google penalize me for using PostJoint?" Towards the end, the article says "As long as you don't let your standards slip just to make a quick buck and follow our guidelines, chances are you will be fine."
Just like MyBlogGuest, there is a high probability that bloggers within PostJoint have been penalized, and if not, likely will be soon. However there is no confirmation yet on this.