Google's Panda update has sent many an SEO into a flurry of activity. The search engine's algorithm tweak requires SEO's to have a renewed focus on having unique content on every page of the site. With today's dynamic Web-based content management systems, there can be some issues ensuring that Google knows which is the preferred version of a page. And with the current focus on mobile design, the problem is magnified as search engines are finding it difficult to determine the right page.
Google of course has provided a solution - support for a format that will allow Web workers to specify a preferred version of a URL if a site has very similar content with multiple URLs. This format is called rel=”canonical” tag which enables you to have more control over the URL returned in search results and helps to ensure that properties such as link popularity are consolidated to your preferred version.
Many sites today are still seeing their mobile pages indexed by search engines. Support for the rel=canonical tag will ensure this does not happen. Simply include the tag into the header of your existing mobile site and it will indicate to Google that the Web version, and not the mobile version, should be indexed.
Though the rel=”canonical” tag will help you in solving your double content problem, Google still does not provide total support. Google says that “It’s a hint that we honor strongly. We’ll take your preference into account, in conjunction with other signals, when calculating the most relevant page to display in search results.” so the rel=canonical element is not yet a directive.