It is what everybody wants. Ranking well on google search results. Being on the first page of the google search results for some keywords is one of the biggest achievements you could ever accomplish as a webmaster.
Now you have one more thing to consider in the battle for search engine ranking. Mobile friendliness.
This is what google says in the webmaster central blog:
Starting April 21, we will be expanding our use of mobile-friendliness as a ranking signal. This change will affect mobile searches in all languages worldwide and will have a significant impact in our search results. Consequently, users will find it easier to get relevant, high quality search results that are optimized for their devices.
Yes, Google uses mobile-friendliness as a ranking signal.
Check out useful links below about mobile friendliness:
Guide to mobile friendly sites: https://developers.google.com/webmasters/mobile-sites/get-started
Mobile-friendly test: https://www.google.com/webmasters/tools/mobile-friendly/
Mobile usability report: https://www.google.com/webmasters/tools/mobile-usability
You can find the relevant post here: https://webmasters.googleblog.com/2015/02/finding-more-mobile-friendly-search.html
Hope this helps.