We already know that there are around 250 factors in Google’s ranking algorithm but Google have officially announced that a new one coming out will affect sites for mobile search.
Starting 21st April 2015 there will be a new ranking factor which will give preference to mobile optimised sites in the search results.
If you are not sure if your site is mobile friendly then you can run a quick test with Google’s official Mobile Friendly Test Tool.
It’s not clear yet if there will be any differential treatment for responsive designs versus a fully separate hosted mobile site.
Since Google have announced this update well in advance of it actually happening we expect this to have some pretty major impact on SEO results so if you need to get either a new web design or get your current site optimised for mobile then we suggest getting it done before April 21st.
You can read the entire official post on the update here