Are Mobile Sites A Duplicate Content Issue?

Apr 29, 2010 • 8:30 am | comments (7) by twitter Google+ | Filed Under SEO - Search Engine Optimization

Bryson Meunier wrote a piece at Search Engine Land named Don't Penalize Yourself: Mobile Sites Are Not Duplicate Content. The article basically explains that if you have a mobile web address, i.e. different URLs for your mobile content, with the same content you have on your main URLs, it is NOT duplicate content. He said, Google is smart enough to figure out your mobile content is not duplicate to your main content - because they are smart enough to know when to show you the mobile content versus the normal content.

He said:

Knowing that search engines index and return mobile content for relevant queries, and that they have blended mobile ranking algorithms to rank mobile content for mobile queries and desktop content for desktop queries, it’s clear to me that they don’t treat mobile sites like traditional desktop duplicate content. Knowing this, it’s a wonder that many mobile SEO experts, including some whose opinions I generally respect, would continue to recommend blocking your mobile site from Googlebot and other web crawlers.

A Sphinn thread has a comment about this from Sebastian who said:

So many webmasters and SEOs are totally ignorant WRT more or less identical content presented on different platforms vs. duplicate content flooding a single channel. Hopefully this piece pushed to the front page will enlighten many of them.

Honestly, what I still don't get is why are webmasters still creating different URLs for mobile content? Why aren't they detecting useragents and showing a different stylesheet for those mobile handsets? I really don't understand why bother with special URLs? I mean, yea, Google is smart enough to know a mobile URL from a non-mobile URL based on the content. But when someone links to your mobile URL, that link doesn't help you as much as it linking to your main URL. I rant about this more over here and give pretty good examples of how this works.

Forum discussion at Sphinn.

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Alistair Lattimore

04/29/2010 01:32 pm

The main reason I see is that they need different content for different devices, which if they used the same URL would be considered cloaking. A good example of that might be a travel web site, which offers indepth content if you're coming via a desktop with lots of screen real estate but a heavily cut down version for a small screen device. The logic in that particular case is simple, the intent behind someone visiting a travel web site via a small screen device is different to those visiting by a desktop. A small screen user might want a phone number, address, opening hours or a last minute reservation while a desktop user is more about research & reservations.


04/29/2010 01:50 pm

Alistair, This isn't cloaking -- just the styles/layout change. Developers have been practicing this for years, writing one set of styles for IE, one for Netscape, etc. This is no different. Plus, the only problem with cloaking arises when you're showing bots something different than what you're showing the user. That isn't the case here, as Google has complete access.

Barry Schwartz

04/29/2010 01:58 pm

Yep, this is not cloaking and this is allowed.


04/29/2010 02:14 pm

But there is only so much you can handle with device-depended style sheets. I'm with Alistair - a travel website's main options and sales funnel architecture are often (and should be) different from the desktop site. Not using client-side scripting also adds complexity to a solution that merely does a 1:1 page redirect based on user agent/device.

Michael Martinez

04/29/2010 06:45 pm

"Honestly, what I still don't get is why are webmasters still creating different URLs for mobile content? Why aren't they detecting useragents and showing a different stylesheet for those mobile handsets?" Because it's easier to just create dedicated resources. You only feel the pain down the road when you have to clean up all the content.

Scott Mc

04/30/2010 12:52 am

As somebody who actually manages a travel web site, I think it's true: The user experience needs to be dramatically different on a smartphone vs. desktop. And most of this complexity cannot be managed with CSS changes. One of the main issues, at least in travel, is the "I'm there now" (likely mobile use case) versus "I want to go there (likely desktop use case). These are very different needs, and the tools to support them are very different. So I agree with Alistair on that front. You could argue that this distinction matters less for travel media sites like Tripadvisor, but it's a real distinction for travel e-comm sites. On the cloaking issue, I still would love somebody to explain why changing layout / content based on user agent is NOT cloaking. It feels like the textbook definition of cloaking! I agree that most people are doing it, without penalty, but has Google ever made a public pronouncement on this issue?

Barry Schwartz

04/30/2010 01:04 am

Scott, as long as the content is the same, it is not cloaking. Google has told us this time and time again. Some more details at And also at Cloaking is: "Serving different content to search engines than to users." Same content, but different UI, is not cloaking. Google does this themselves, all the time.

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