On June 11th, Google announced through a blogpost on webmaster central that they will, in the near future, be rolling out a ranking update within their algorithm that will be directed towards reducing the rankings of websites that are not built with mobile optimized designs.
If your site does not have a mobile sub-domain or a responsive design, be prepared for what could be a very large decrease in traffic from mobile devices from Google.
With most of our clients in the neighborhood of showing trends of approximately 20% mobile traffic, this could be a very large impact across the web. Within industries that mobile design is not as prevalent, such as the pharmaceutical sector, instantly brands could see their search footprint dramatically reduced.
If your business already operates a mobile subdomain or deploys a responsive design, you will likely be not impacted by this update. If your business renders your native version, then undoubtedly you will see an overall reduction in traffic by time this update rolls out to all of Google’s data centers.
Within the Google statement, the following aspects could trigger the reductions, outside of just serving a native site.
Essentially this is not re-directing users to the appropriate page within a mobile experience. An example of this would be automatically re-directing all pages within your desktop site to the mobile homepage within any mobile session.
Smartphone only errors
The key here is limiting 404 (i.e. “file not found”) errors when mobile pages do not exist. When users land on a desktop page that does not have mobile equivalent, be sure to re-direct the user versus serving the error. Also mentioned by Google is infinite loops that frequently happen to Google mobile crawlers when re-directed.