Until now, your website needs to be optimized for mobile access. If it is not, you have about 3 weeks left, as of the time of writing.
Mobile user experience is evolving over the past decade, with a greater percentage of online searches are done on mobile devices every year. Solving this trend, Google has made great efforts to accommodate mobile audience, tailoring search results in favor of sites that are properly optimized for mobile use.
Incentive ranking you get from having your site optimized for mobile has been significant, but not overwhelming. Millions of websites have gone just fine, although not optimized for the mobile user experience, and yours may very well be one of them. Unfortunately, this vacation will not last much longer.
Just another update?
Search giant seems to make almost constantly updating their records search. You will be forgiven for thinking that this upcoming April 21 update is something like the last few we've seen-and data refresh or some small tweak that leads to an almost imperceptible changes in the search engine rankings for a small number of businesses.
Unfortunately, currently non-optimized businesses, this does not appear to be the case. One of Google's recently explaining that this latest expansion algorithm is set to have a greater impact than any Panda or Penguin and given the Panda and Penguin algorithm updates are the largest that we have seen from Google, this new mobile update can be fully change how you look at search.
April 21 time cannot hold any special meaning, but overall motivation of Google Update is clear. In fact, it's the same motivation is driven by their other game-changing algorithm changes as Panda, Penguin and Dove.
At its core, Google wants users to have a great online experience. They want their users to easily find exactly what you want, and they want their users to complete a high quality, easy-to-use websites. This is why they have rolled Panda, which favored sites with high-quality content and Penguin, who are weeded out sites using spammy practices offsite, and that is why they are making the move to improve the mobile Internet experience with this update April 21.
You may already have a mobile SEO strategy in place, if this is the case, chances are, you're already set. The new algorithm change will not have much effect on you, though you can see a jump in rank as non-mobile-friendly competitors occupying points above you in the rankings fall under you. On the other hand, if you have yet to optimize your website to be mobile-friendly, you should take action immediately with these three steps:
Make sure your site is optimized for mobile phones. This may seem obvious, but it is the most important step. You can host a separate, mobile friendly version of your site or just implement responsive design to be compatible with all devices. However you do it, make sure that your site is properly accessible from any device.
If you are confused about what is and is not considered a "mobile-friendly," Google can help. Although the details of the update on April 21 is still under wraps, Google does not offer its own mobile friendly test, which can help to determine the compatibility of your site. In addition, you can check Usability Report Mobile in Webmaster Tools to ensure your site to be found without errors.