Google: you need a mobile-friendly site by 21 April

This month sees a significant change coming from Google regarding how it treats sites that are not mobile friendly:

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.
— Takaki Makino, Chaesang Jung, and Doantam Phan

This basically means that from April 21, if you don't have a responsive or mobile site, you are likely to take a significant hit in mobile search results. 

To check how mobile-friendly your site is, and get some advice on how to make it more mobile friendly, I'd recommend checking out Google's advice on mobile friendly websites here.

This update to Google's algorithm is a very important one and will have big implications for most businesses - so if your site is not mobile-friendly, I would advise that you take any necessary steps as soon as possible to make it so before the April 21 deadline. For more information and resources on the algorithm change, you can check out Google's blog post about it here.