April 21 Is Your Last Chance for Mobile Optimization Before 'Mobilegeddon' The search giant is currently working on a major algorithm change that will revolutionize the way mobile friendliness is determined.

For years now, mobile usability has been a factor in Google's search algorithm. Sites that are optimized suitably for use on mobile devices rank higher than their non-optimized counterparts, even on desktop devices. But until now, that ranking factor has been both limited and ambiguous.

Aside from a "mobile-friendly" tag associated with various sites in mobile search results, it hasn't been entirely clear which factors Google considers when calculating mobile rankings or how many sites (or which ones) are currently affected. Because of this, many business owners have postponed or avoided optimizing their sites for mobile devices, and have survived to tell about it.

Starting April 21, that's all going to change.

Related: 7 Musts to Maximize Your Company's Mobile Strategy

According to a recent Google blog post, the search giant is currently working on a major algorithm change that will revolutionize the way mobile friendliness is determined. Starting on April 21, this new algorithm will be gradually rolled out worldwide, affecting mobile searches in all languages in all corners of the globe.

Scope of the update

If you're aware that Google already considers mobile usability as part of its ranking calculations, you might wonder why this April 21 deadline, dubbed "mobilegeddon," is important.

It's true that many of Google's "updates" are actually just data refreshes and tweaks that hold little bearing on existing search rankings. However, Zineb Ait Bahajji, a member of Google's Webmaster Trends team, was quoted at SMX Munich as saying that the new mobile-friendly algorithm change will have more of an impact on search rankings than either Panda or Penguin, two of the largest and most impactful search algorithm updates Google has ever launched.

For now, we don't know much about the update itself, so it's not entirely clear what that impact will be. We do know that it will change the way Google evaluates the mobile-friendliness of websites, but we don't know what new factors will be added or how dramatically these factors will be able to change a website's search visibility. Given Bahajji's comments, it's reasonable to guess that the majority of non-optimized sites on the web could see significant decreases in search visibility.

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The trend toward mobile search

By some estimates, more than 60 percent of all Google searches are now performed on mobile devices, so it makes sense that Google wants to capitalize on this traffic and ensure the best possible experience for its users.

In addition to the upcoming algorithm update, Google is already starting to roll out ranking changes based on information from indexed apps of signed-in users. This may have a major impact on how search results are displayed as well as what type of results are displayed. While traditional search results exclusively display websites, future search results could focus on apps and other mobile tools.

However search results progress, it's clear that the companies who cater to mobile users best will earn the most visibility from Google.

Related: Here's Why You Need to Make Sure Your Site Is Mobile-Friendly by April 21

How to prepare

If your site is already mobile-friendly, you won't have much to worry about. However, if you've not yet implemented a mobile strategy for your online presence, now is the critical time to get it done. Follow the steps:

• Ensure the mobile version of your site is active and functional. Responsive designs are the most popular, but you can also have a separate hosted mobile version of your site. Google doesn't have a preference, as long as mobile users' experience isn't interrupted.
• Ensure Google's mobile bots can crawl your site. If Google can't see it, it may as well not even be there.
• Check each individual page of your site on a mobile device to ensure navigability. Just because your home page is mobile friendly doesn't mean the rest of your site is.

You may find the following resources helpful:

• The Definitive Guide to Mobile SEO
• 5 Wordpress Plugins to Help Create a Mobile-Friendly Website
• The Key Ingredients to a Winning Mobile Content Marketing Strategy

Google additionally offers two tools you can use to check whether your site is mobile-friendly. First, you can use the appropriately named Mobile-Friendly Test to see whether your site meets initial qualifications. It's not entirely clear whether this checklist will cover all the factors the April 21 update will introduce, but since it's coming straight from Google, it's safe to assume it's fairly reliable. Google Webmaster Tools also contains a convenient Mobile Usability Report you can run to examine your website as Google sees it. If you find any errors or discrepancies, you have roughly one month to get them all fixed.

This April 21 Google update looks to be the biggest mobile-related algorithm change we've ever seen, but I'd bet money that it isn't the last. If you don't have a mobile version of your site in place by April 21, your search visibility could be seriously hindered.

At this point, you may not need a dedicated app or all the bells and whistles of a dynamic mobile user experience, but beware: Google wants its mobile users to be happy. It's on you to get the job done.

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