According to Google, hosting content in a subdomain or subfolder of another entity’s site isn’t against its guidelines, but that it’s improving is systems to recognize that content and treat it accordingly. This came from the Google Webmasters Twitter account on August 14.
Here is what the tweet said:
“We’ve been asked if third-parties can host content in subdomains or subfolders of another’s domain. It’s not against our guidelines. But as the practice has grown, our systems are being improved to better know when such content is independent of the main site & treat accordingly.
Overall, we’d recommend against letting others use subdomains or subfolders with content presented as if it is part of the main site, without close supervision or the involvement of the primary site.
Our guidance is if you want the best success with Search, provide value-added content from your own efforts that reflect your own brand.”
The reason why somebody would want to do that is because third parties are interested in renting out another brands subdomain in order to get a leg up on the competition when it comes to search rankings. That would help the site get more traffic and conversions.
John Mueller of Google touched on this subject during a Google Webmaster Central office hours session on June 28 saying, “I know the search leads at Google have been talking about this exact topic for a while now to try to find ways to handle these appropriately. By ‘handling them appropriately,’ I don’t mean we should treat them as spam and just delete all of these subdomains, because they’re not really spam. They’re just kind of sales pages, affiliate pages that are hosted within another website. Maybe the right approach is to find a way to figure out what is the primary topic of this website and focus more on that, and then kind of leave these other things on the side.”
Mueller then went on to say, “When it comes to quality, we try to look at the quality of a website overall. So, if there are particular parts of a website that are really low quality …. then overall, that could be degrading the quality of that site a little bit.”