Google has made no secret of its upcoming algorithm release; and its a big one! The impact of this particular release could be more broadly felt than Panda and Penguin combined. Why you might ask? This release is targeted at mobile-only searches, that is, users who are conducting Google searches from their mobile device(s). These days, that works out to be about 50% of all Google queries. The update will have an international impact, effecting searches across all languages.
When Is The Change Slated to Happen?
According to Googles Webmaster Central Blog, the update will occur as of April 21.
What Can I Do To Prepare?
If your website is not already mobile-friendly, that would be your first priority. If your website is mobile friendly, its best first line of defense against being penalized by Googles mobile-friendliness ranking signal is to use Webmaster Tools Mobile Usability Report. You can also test any website using Googles Mobile Friendly tester. These tools will allow you to see any mobile usability errors that Google detects on your website that would effect its mobile-friendliness. If you do detect mobile page errors on your website, it would be advisable to have those repaired before the April 21 update to avoid being penalized by Google.