April 21st is the day that Google threatens to reduce the visibility of your website or blog in search results if it is not "mobile-friendly."
I have been reading posts about this April 21st Google deadline for weeks, listening to podcasts, and knew this was coming, yet did nothing until last night jumping into a "beta" version of Typepad so that I could format all the colors and choices myself.
The issues surrounding mobile usability could have a profound affect on how your business will show up in Google search results. For example, Google says that 100% of my website pages have mobility issues. This is a nightmare!
In summary, the reason for this mandate is that more and more people are using their smart phones and tablets to access the web.
Try the free Google mobile-friendly test for any page on your website. Let me know what it says.
Helping users find mobile-friendly pages