How Bing and Your Mobile Device Became Friends

As we discussed in Meet our Mobile Bots recently, Bing probes websites using device-specific crawlers to understand if they provide a good experience on different devices and platforms and to inform our mobile ranking algorithms. Today we are joined by Mir Rosenberg from the Mobile Relevance team to add some color to the subject by discussing a recent mobile ranking update that resulted from this effort. Enjoy!  — Vincent


Traditionally, Bing wasn’t heavily relying on specific device and platform signals to provide web results to the user. You would get similar results on your PC, Mac, or smartphone for most of your searches.

However, we live in a mobile-first, cloud-first world and we need to think about our users’ search experience on mobile devices differently. As a result, we’ve been really intensifying how we look at web results across these mobile devices. We have a long and exciting journey ahead of us, but as a very first step in this long-term investment, we started probing web pages for “mobile friendliness” and ranking web pages accordingly on our users’ mobile phones.

Why is Mobile Relevance Important?

Most of you search from your mobile device more frequently than a year ago, some of you almost exclusively search from your phones. What’s more, comScore expects the number of mobile web users to surpass desktop users for the first time this year:

Mobile web usage expected to outpace desktop in 2014 - (c) Image: comScore

You likely already know this from your own server logs or analytics package: the number of people visiting sites from mobile searches has been growing, too.  So we want them to be happy on Bing (and, by extension, any Bing-powered search) — not just on the PC or Mac but also on their phones.

So when they are using their mobile device, Bing should just know, and Bing should respond differently when it comes to web results.  Sounds easy, right?

Mobile Challenges

There are several interesting challenges for mobile relevance when compared to “traditional” relevance. For instance:

  • It is easy to type URLs on PCs and Macs, but it’s more cumbersome on phones
  • Some sites have mobile-incompatible content. For example, a non-mobile friendly search result may send you to a page with fonts or buttons so small that you can barely use it without zooming or pinching — if at all
  • Some pages that work fine on a PC or Mac can be useless on some mobile devices, think Flash-only pages on iOS
  • In some cases, the “normal” URL redirects to a mobile version, which not only wastes user’s time but also consumes bandwidth on their data plans

All of these user challenges and more were used to inform how we rank pages on mobile devices.  For a subset of queries, we made a number of changes that prevent users from getting non-device friendly results such as:

Example of pages not really giving users the best of experiences on a mobile device

…to results that work well on their device of choice:

Type of page we prefer with the new update

These are a few examples of our journey towards increased awareness of mobile friendliness for the pages we rank.

So how has our recent update – which affects a subset of all our mobile searches — changed our search results? Let me demonstrate by searching for Matt Damon (who, coincidentally, is my favorite actor… no seriously :) )

Example of Bing mobile results for "Matt Damon", before (left) and after the update (right).

In this example, we know which pages are mobile-friendly so automatically rank them higher with the new update, whereas previously the searcher would have had a much bigger change of landing on a non-mobile friendly page or possibly had to wait for a redirect to a mobile-friendly page.

Mobile Ranking Techniques

As always, there are many ranking factors at play — and mobile raking has its fair share of Secret Squirrel stuff — but here are some of the things that we do to improve mobile relevance:

  • We identify and classify mobile and device-friendly web pages and websites
  • We analyze web documents from a mobile point-of-view by looking at:
    • Content compatibility
    • Content readability
    • Mobile functionality (to weed out “junk”, that is pages that are 404 on mobile or Flash only etc.)
  • Return more mobile-friendly URLs to the mobile SERP
  • Ranking the results pages based on all of the above

What Site Owners Can Do

Not all sites follow the same mobile site or content strategies, so this creates challenges to all search engines. Ideally, there shouldn’t be a difference between the “mobile-friendly” URL and the “desktop” URL: the site would automatically adjust to the device — content, layout, and all. That’s why we continue to recommend you use responsive designs over separate mobile (m.*) sites and ensure a great experience for users on all devices and avoid compatibility, readability, and functionality issues. Also, make sure to heed the recommendations in Meet our Mobile Bots and allow our crawlers access to all necessary resources.

What’s Next?

The recent update marks the beginning of our journey towards increased mobile relevance and is now improving a small but steadily growing percentage of our mobile queries. There’s lots more to come. So look out for more news about this topic soon!

Mir Rosenberg – Principal Program Manager

Mobile Relevance Team