In November, Bing principal program manager Mir Rosenberg wrote in a blog post, “We started probing web pages for ‘mobile friendliness’ and ranking web pages accordingly on our users’ mobile phones.”

Bing had begun using mobile friendliness as a ranking signal for a “small but steadily growing percentage” of mobile queries. Apparently that growth was pretty slow, as a full roll-out is still only on the horizon.

In a new blog post, Bing’s Shyam Jayasankar announced that Bing “will be rolling out mobile friendliness as a signal in ranking.” Apparently the older announcement was just about future plans, thought it didn’t make it sound that way. Either way, like Google, Bing also cares if your site is mobile-friendly.

Last month, Bing began labeling results as “mobile-friendly” just like Google started doing last year as it prepared to get sites ready for the algorithmic adjustment.

Here’s an example of how results might change as a result of the mobile-friendly signal:

Bing isn’t saying exactly when the update will fully roll out, but you probably won’t need to worry about it too much if you’ve already made your site mobile-friendly for Google users or are in the process of doing so.

As an added bonus, Bing is working on a tool to help webmasters analyze webpages using its mobile-friendliness classifier. This will become available in a few week. Or you could probably just use Google’s.

More about Bing’s mobile-friendly efforts here and here.

Google’s mobile-friendly update didn’t have quite the major impact on search results that many expected. Will Bing’s?