Our approach to mobile-friendly search

Mobile search continues to surge ahead and grow as a percentage of overall internet search queries. In November 2014, we shared our plans to make significant investments towards understanding the mobile friendliness of web pages. Since then, we have been investigating various approaches that leverage mobile friendliness to deliver the best possible mobile search experience on Bing. In this update, we share details on our mobile friendliness roadmap, insights from recent user experience changes and factors that impact mobile friendliness of webpages.

Mobile-friendly tag in search results

You might have noticed we recently started tagging search results as “Mobile-friendly”. This enables the user to skim through the search results to know which ones will quickly answer their information needs. Here is an example of how this tag appears on the search results page:

Mobile-friendly tag

We received great feedback from this change in user experience showing that users strongly prefer pages marked with the mobile-friendly tag. Based on data from user’s interaction with Bing, we have seen that mobile users are able to satisfy their information needs much faster on searches that return more mobile-friendly results. With that in mind, we will be rolling out mobile friendliness as a signal in ranking.

Ranking mobile-friendly webpages

Our approach to mobile friendliness as a ranking signal balances the need to improve the ranking for mobile-friendly pages, with the continued focus on delivering the most relevant results for a given query. This means that for mobile searches on Bing, you can always expect to see the most relevant results for a search query ranked higher, even if some of them are not mobile-friendly. While the changes will improve ranking for mobile-friendly pages, webpages that are highly relevant to the given query that are not yet mobile-friendly will not get penalized. This is a fine balance and getting it right took a few iterations, but we believe we are now close. We expect to start rolling out mobile friendliness ranking changes in the coming months. In an effort to work hand in hand with our Webmasters and ensure a smooth transition to a mobile-first world, we will continue to share details on the roll-out of our mobile friendliness ranking technique through updates on this blog.

We have also been working on a tool that will allow Webmasters to analyze webpages using our mobile friendliness classifier and help them understand the results. This tool will become available in a few weeks from now and help Webmasters find and fix areas of their site that suffer from mobile friendliness issues. Understanding the factors that influence mobile friendliness will help serve our growing mobile user base much better.

Factors determining mobile friendliness

Over the past few months, we have been working diligently on improving our mobile friendliness detection algorithms. We can now tell with high precision if your webpages will render well on mobile devices or not. How do we know? We consider a number of different factors in making this determination. Some of the more important factors are detailed below:

1. Navigation – The menus, buttons and links on the page should be large enough and spaced well apart to aid touch-based navigation. In the example below, you can see the large, easy-to-tap and distinct navigational elements on the mobile-friendly page. In contrast, the page on the right has hyperlinks that are too close to each other and could be prone to accidental clicks from mobile users.

Navigation example

2. Readability – The text on the page should be readable without requiring zooming and lateral scrolling to access specific content. Keep in mind that readability is influenced both by font size and the viewport settings (defined in HTML tags). Here is an example of how readability impacts the mobile friendliness of the page:

Readability example

3. Scrolling – The content of the web-page should fit within the device width. Vertical scrolling is considered acceptable, but the need to scroll horizontally hampers the ability to consume your content easily. Well-designed mobile pages typically fit well to the device width in both portrait and landscape orientations.

Scrolling example

4. Compatibility – The content needs to be compatible with the device. For example, pages with flash content do not work well on iOS devices as discussed earlier in our November 2014 post. This also applies to videos that cannot be played on mobile devices due to plugin dependencies, copyright issues or distribution decisions made by the content owner. We check for hints in the content rendered on the page to determine if any compatibility issues exist.

Compatibility example

Typically all the factors above will need to be met for a webpage to be considered mobile-friendly by our classification algorithm. There are more factors that we are considering along the lines of mobile friendliness, like the friction that pop-ups sometimes create in navigating to the core content of the page. One important thing to remember – we depend on access to all the necessary CSS and script files required by your page to make this determination. So, it is important that you allow Bingbot mobile user agents access to download these resources.

Let’s go mobile!

Our priority is delivering the best search experience for our customers, and we are committed to evolving Bing search to ensure that we are delivering the most relevant and helpful results. Mobile-friendly webpages are key to satisfying on-the-go information needs, so it is important to optimize sites for an increasingly mobile user base. We are very interested in hearing your thoughts on mobile friendliness and any feedback you may have on our plans. Join the conversation about mobile ranking – give us your feedback through the Bing Listens portal! Let’s go mobile!

On behalf of the Bing Mobile Relevance Team –

Shyam Jayasankar