November 4, 2014

Bing’s new mobile crawlers – and what it means for your mobile SEO

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Following Google’s lead – as it often does – Bing just announced changes to its mobile SEO crawler and processes which affects how sites are crawled, selected, indexed, and ranked. Outside of Barry Schwartz at Search Engine Land, the news went relatively unnoticed. But don’t let the lack of coverage fool you – this announcements requires action, particularly for the 75% of top retailers using m. or dynamic-serving mobile sites.

According to mobile SEO research on the IR500, 60% of retailers use m. sites to reach their mobile audiences. Several of these – some of which are highly recognized retail brands (e.g. Target, Staples) – are not detecting and routing Windows phones to mobile-friendly pages. Meanwhile, many brands that employ dynamic serving techniques for mobile audiences (e.g. Overstock, Office Depot) are not serving mobile-optimized content to Windows Phone users.

Why Bing’s announcement matters
What I find most interesting about Bing’s new mobile bots is the dynamic approach being taken. Google’s mobile bot takes what might be thought of as a static approach, that is, it only looks for iPhone-served content to make a judgment about a site’s overall mobile-friendliness for mobile users. Bing, on the other hand, seems to want to learn how a site adapts to other popular devices, too. This will include Windows Phones, of course, along with iPhones and, one assumes Android devices – although (perhaps not surprisingly) Bing’s announcement makes no mention of their Android crawler.

Following the dynamic user agent formula Bing outlined, the Bing mobile bots for iPhone 7, Android 4.3, and Windows Phone 8.1 should identify themselves along these lines:


Mozilla/5.0 (iPhone; CPU iPhone OS 7_0 like Mac OS X) AppleWebKit/537.51.1 (KHTML, like Gecko) Version/7.0 Mobile/11A465 Safari/9537.53 BingPreview/1.0b


Mozilla/5.0 (Linux; U; Android 4.3; nb-no; GT-I9300 Build/JSS15J) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30 BingPreview/1.0b

Windows Phone:

Mozilla/5.0 (Windows Phone 8.1; ARM; Trident/7.0; Touch; rv:11.0; IEMobile/11.0; NOKIA; Lumia 530) like Gecko BingPreview/1.0b 

For context, Bing also expresses in the announcement their strong preference for responsive design sites over dedicated mobile sites, advising, “To safeguard the best mobile search experience for your users, move towards a responsive model that adapts to your user’s device at the same URL.” Perhaps simultaneously realizing that for many marketers, responsive design remains an aspiration, the launch of these new mobile bots seems to be a concession of sorts to improve the mobile experience for Bing’s mobile searchers while not penalizing sites that have not yet gone responsive.

We expect Bing to use this information to further personalize their mobile search results to a searcher’s device. In short, if your site is not optimized for mobile, your rankings will suffer.

Rank higher in Bing results
The biggest takeaway for marketers who want to rank well in Bing mobile results is to make sure mobile site redirects and/or dynamic content serving logic is setup to identify and route Windows Phone users (and bots) to optimized mobile content. Many do not.

And yes, you should do this despite the Windows Phone’s own ironic browser user-agent hack (Windows Phone 8.1 Internet Explorer fakes its user-agent string by including the words iPhone and Android since doing so means Windows Phone users get to hitch a ride on any mobile user agent redirect schemes used by websites to route iOS and Android devices). Older Windows Phone devices (such as the ones used in the Bing mobile bot strings) do not use this hack and require server-side or browser-side targeting logic to get routed successfully.

No doubt we’ll be hearing more mobile SEO recommendations from Bing as they work to optimize their mobile searcher experience. Until then, I’d still assume that Google’s information architecture requirements for dedicated and dynamic mobile sites (such as using 302/301 mobile redirects, serving the Vary by User Agent HTTP header, using switchboard tags, etc.) still apply. But definitely watch this space!


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