Last week during SMX Munich (Search Marketing Expo), Google Webmaster Trends analyst Zineb Ait Bahajji said that Google’s upcoming “mobile-friendly” algorithm update on April 21st will have more of an impact than both Panda and Penguin

[1]. Considering the huge impact of Panda and Penguin, this is a big deal. Here are some common mobile missteps that can negatively affect your rankings:


  • Blocked JavaScript, CSS and image files
  • Unplayable content
  • Faulty redirects
  • Mobile-only 404s
  • App download interstitials
  • Irrelevant cross-links
  • Slow mobile pages




Will any of these impact you? Let’s review each one by one.


Blocked JavaScript and CSS


Blocked JavaScript, CSS and image files are generally caused by a robots.txt issue [2]. Robots.txt is a special file on your website which defines which resources are indexable by Google and thereby how Googlebot interprets your page. If Google cannot access critical JavaScript and/or CSS, it will assume it’s equally unusable by users and your website’s rankings will suffer. And if the issue is more than Googlebot-deep, your users and thereby your bottom line will suffer as well.


Unplayable Content


Unplayable content refers to videos or other content that cannot be played on mobile devices, such as Flash video or license-constrained media. Not only are these frustrating for users, but Google will penalize you for poor mobile experience.


A great alternative to Flash, or other proprietary video formats, is using HTML5 video like YouTube, Vimeo or directly embedded webm file. The benefit ismeeting Google’s content accessibility requirement and extending viewership to privacy-conscious users who might block Flash and similar proprietary technologies.


Privacy protip: Use HTTPS (SSL/TLS) to secure your users’ sessions. HTTPS encrypts your users’ sessions such that the delivered content is authenticated and resistant to malicious modification. Security and privacy conscious users will give a thumbs up, and it might be required for HIPAA compliance. Google considers it a ranking factor, too [2].


Another Privacy Protip:  Instead of using normal to embed videos, use Your users get the exact same experience, but without the annoying third-party tracking cookie from Google / YouTube, which is good practice for practices with a worldwide user base where cookie laws are stricter than in the United States.


Faulty Redirects


Faulty redirects can cause usability issues where two versions of your website are not properly redirected. For instance, redirecting to is OK. But the page on, redirecting to the mobile homepage,, is bound to frustrate your users and makes your website difficult to navigate [3].


Mobile-only 404s


Mobile-only 404s can cause issues as well. For example, if a corresponding page does not exist on the mobile-redirected version of the same site, then a hard 404 will result. That would generally mean the destination page would be dropped from Google’s index and no longer display for mobile searches. For example, if the user requests, but does not exist, then you get a 404 [4].


App Download Interstitials


“App download interstitials” are large banners that take up a significant portion of the page and tell you to download their app before you can continue. Don’t you love it when you go to a page, see the content for a split second, and then a second later, get a large ad about their app that takes up 95% of the screen? Yeah, no one else loves it either. So if you’re currently doing that, stop it. Your SEO or CRO web team should have spotted this issue by your extraordinarily high bounce rate, but in case they haven’t, trust us – it’s a terrible practice and almost universally hated by users [5].


Irrelevant Cross-Links


Irrelevant cross-links are fairly simple to find and fix with a quick internal link audit. Cross links are when a page on a desktop-optimized version links to a mobile version or vice versa. The same also applies to HTTP and HTTPS versions of a site.


Whereas redirection occurs at the web server level, cross-links are a result of poor link practice [6]. For example, using absolute links can cause this issue. Absolute links are links that include the fully-qualified domain name as well as the page, e.g. and “/contact-us”. If we had two different versions of our page for mobile and desktop, then we could cause an issue by putting a link to on the desktop site, or on the mobile version. Using relative links fixes this issue seamlessly, e.g. “/contact-us” instead of the full path. This way, whether you’re on (which doesn’t exist) or, you still directed to the right resource.
Similar issues can be caused with HTTPS. If you don’t have HTTPS forced for all URLs, if you miss a single HTTP absolute link, you can nullify the HTTPS session and accidentally cross-link your user to the HTTP / insecure version of your website. That’s why it’s always a good idea to use server directives to force HTTPS and relative links where possible.


Slow Mobile Pages


Slow mobile pages are also an issue [7], especially since mobile data tends to be slower than WiFi. Depending on your platform, speeding up your website might be as simple as installing a couple plugins, or it might be a massive undertaking. Ideally, your mobile page should render in one second or under. While that’s a tall order for some sites, it’s a goal to work toward.


The bottom line is that mobile makes up approximately half of the user market, so the days of mobile friendliness being a luxury are gone. Mobile is a must. Can you afford to lose half of your website visitors?


If this is all Greek to you, send this link to your SEO or web developer. If it takes them by surprise, it might be time to “make a change”.


We want to hear from you! Are you prepared for the algorithm update? Let us know in the comments.