This is a real example from one of our clients.
One of our clients wanted to build a mobile version of their site and contracted a development company to design, build, and implement the mobile version and host it on http://m.clientdomain.com
They did a fabulous job, the layout is really optimized for mobile devices and looks fantastic. Our client has a large site (over 100,000 pages) and the content was reformatted efficiently for mobile consumption.
One problem – we as their SEO firm did not know about this site until 5 days after launch.
A quick review showed the following problems – all which could have resulted in our client being severely penalized. Google sees m.clientdomain.com and www.clientdomain.com as 2 separate sites – with the exact same content! It is clearly documented what happens to sites with duplicate content.
As an immediate fix – we setup our robots.txt not to spider or index the m.clientdomain.com site. That will avoid any problems until we’re able to put in the proper code to avoid penalties.
Thankfully there is an easy fix: canonical urls. These give Google and other search engines a flag that yes the content is duplicate and provides a mapping to where the original is. Search engines use this to attribute the value of content to the original page.
This is a disaster after all
We laid out how canonical urls could be included into the mobile site as step one for the mobile site SEO, then discovered when the original spec for the mobile version of the site was put together and provided to the developer, SEO was not taken into consideration. No efforts to identify the page from the original site were made in order to provide the canonical reference within the mobile pages.
The mobile site cannot be indexed with duplicate content. Unfortunately our client will either have to spend thousands in redevelopment to provide proper url mappings, or exclude the mobile site from search altogether.
Engineering the mobile site with search engine optimization would have meant we had proper canonical urls, mobile sitemaps, mobile search optimization, and more all part of the development. We would have avoided this disaster altogether.
Search engine optimization really isn’t an add-on. Sites that are engineered with SEO in mind get better search penetration, more traffic, and will be able to benefit not just from regular and mobile versions, but all efforts working together.