Having specialized in mobile SEO for about as long as people have been talking about it, I have seen many experts say many things about the practice of making content accessible to and optimized for mobile users. Not all of these things make sense. There are two things specifically that I want to call out today that have somehow persisted as mobile SEO best practices, even though following them could actually make you less visible to mobile users. There may have been a time and place for making these recommendations in mobile SEO, as the landscape has changed dramatically even in the last five years. But if you hear them brought up in 2009 and beyond, check the speaker�s business card, as they may be your competitor trying to sabotage you in mobile search. More likely they�re well-intentioned, but not considering all aspects of the issue. To be safe, take time to educate yourself on how and why to avoid these two worst practices.

1. Block your mobile site from Googlebot

The idea behind this recommendation is one that makes sense in desktop SEO, where duplicate content issues abound. In desktop SEO, if you have two sites with the same content, and you don�t identify one site as the canonical site that should receive all of the link popularity, Google will identify one site as canonical and suppress the other one.� �If all of your marketing efforts go into promoting the suppressed one, you�re fighting an uphill battle to make it visible, as Google is promoting the other one. The best practice in desktop SEO is to identify the canonical site with the canonical link element and/or permanent redirects, and block the duplicate content through robots.txt, noindex nofollow or some other means. Some consultants apply this same logic to the mobile world and come to the conclusion that only one version of a site should be in the mobile index and only one version of a site should be in the desktop index.

The reason why this is harmful in mobile is that a different dynamic is often present in mobile search than desktop search. Mobile search engines like Google return mobile sites in desktop results when appropriate, and desktop results are the default for most smartphones. Mobile sites are not suppressed, but oftentimes appear alongside of desktop results, giving brands an additional listing on the page for navigational brand searches. If a webmaster blocks one version of the site from the index, particularly in Google, this will result in one less listing in the mobile search results; and one less listing in a condensed, more competitive mobile search result could make the brand less visible.

This is also emblematic of another, larger issue in mobile SEO: allowing a mobile-formatted version of your desktop site to be your brand�s only mobile presence. �If you didn�t invest in mobile at all, you could let users go to a transcoded or unoptimized version of your desktop site, which may not be usable on a mobile device but would probably show up in search results for certain desktop queries. But if you wanted to optimize your site for search you should be doing mobile-specific keyword research, paying attention to the mobile user experience and including content that is of primary interest to mobile users, which is probably not available on your desktop site. Add value to the mobile user, control mobile signals like sitemaps, domains/subdomains, content-type et al and leave the delivery to the engines for the most natural search visibility.

Another reason I�m surprised many mobile SEO consultants recommend this is that Google specifically addresses it in the mobile webmaster guidelines:

Make use of the robots.txt file on your web server. This file tells crawlers which directories can and cannot be crawled. Make sure it’s current for your site so that you don’t accidentally block the Googlebot-Mobile or Googlebot crawler.

When it comes to mobile accessibility and white hat SEO, it’s best to ignore the commonly argued worst practice and follow these associated Mobile SEO best practices:

1. Don�t block your mobile site from Googlebot and your desktop site from Googlebot mobile
2. Don�t make your mobile site exactly the same as your desktop site, but smaller. Consider the unique mobile context and build a mobile user experience that adds value to a mobile user, using the queries mobile users will use.

2. You don’t need a mobile site

I explained this one in detail earlier at Search Engine Land, but the notion persists regardless. The idea behind this is that in an iPhone-centric world, search engines often return desktop results to mobile users. Those who would say that you don�t need a mobile site are usually cognizant of this fact and take it to mean that a mobile site represents the past rather than the post-iPhone present and future. Yet when it comes to mobile ranking, many search engines prefer the mobile-optimized content and will rank it ahead of desktop results when that content is available.

At Searchology 2009 Search Quality Engineer Scott Huffman echoed his colleague Ankit Gupta and explained Google�s tendency to do this in detail in his discussion of blended mobile ranking (emphasis is mine):

Another element of complete that of course is one of Google�s tenets is that we want to let you search the whole web, and in the mobile world the whole web is more than just the whole web that we normally think of. There�s another web, if you like, that we call the mobile web. And all I mean by the mobile web is sites and pages that are really optimized and made for mobile devices, right? Things you probably don�t want to return very prominently on the desktop but they�re very important results in mobile search. In the US you get things like CNN and other prominent sites where what they�ve done is taken their, typically taken their desktop site and made a nice mobile rendering of it for mobile users. In places like Japan and China, in fact, you have a very large mobile Web of sites like mixi and a lot of others that are either primarily used in a mobile paradigm or use case or are, in some cases, only available on mobile devices, and so of course it�s very important for us to use those to return those results properly when people are searching for mobile.

I�m not going to try to read all of these queries to you or anything but in these screenshots the red results are mobile optimized results from the mobile web and the blue are web, kind of normal web results that typically users on most devices in Japan would see through a transcoded view when they click on it. And my only point with this slide is just to say that you see all the way arranged from at one side queries where there are a lot of good mobile results and so of course our bias in some sense is to kind of return those when they�re available and give you the good easy to use mobile things when they�re there but of course because the desktop web is much bigger a lot of times there aren�t as many good results in the mobile web and so in those cases we�ll return almost all or in some cases all desktop web results to you.

So, yes, they return desktop results to mobile users, but they prefer mobile-optimized results. If there were a number of well-optimized mobile sites available for a particular mobile query, it�s unlikely that any desktop results would appear, and the question of whether or not brands need a mobile site might look very different. Therefore, when I answer the question of whether or not brands who wish to be competitive need a mobile site for a client it is with a resounding yes. Of course it�s necessary to ensure that your mobile content adds value beyond your desktop site, but in general for the past several years mobile optimization has been nearly synonymous with mobile content creation. If you create a well-optimized mobile site, an accessible desktop site and mobile app(s), you will be more visible in search results than a company that only makes an accessible desktop site.

As optimizers, I think it�s our duty to educate our clients on what will help them be more visible than their competition, and not just help them save money. To that end I recommend that they take what they might hear from some mobile SEO consultants with a grain of salt, and follow this best practice instead:

1. Mobile optimization is mobile content creation. If you�re trying to target mobile users, search engines like Google will reward you for providing mobile-specific content.

Hopefully this post helps clarify the situation, and helps explain why these commonly argued mobile SEO best practices are not actually best at all.