Per Google’s latest update into their search algorithm, Google have now released a pending update that could be troublesome for those with older sites that do not work well on mobile.
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.
SUMMARY: IF YOUR WEBSITE DOES NOT WORK TO GOOGLE’S MOBILE STANDARDS BY APRIL 21, 2015 YOUR WEBSITE WILL FACE SEARCH RANKING PENALTY
(Google has yet to let us know what that penalty will be).
It turns out one of the pieces of Google’s new mobile friendly criteria, actually will display a false positive if you have your robots.txt excluding folders that Google wants to check for formatting. This opens a whole can of worms with regards to directory structure, cms based sites.
NOTE: Google’s Developer Teams lead also makes note of problems with the webmaster tools, and page speed index.
UPDATE APRIL 29,2015 – For those who haven’t seen any change in analytics please keep in mind the propagation time to reindex pages under new google mobile search criteria…see Google’s webmaster blog – http://googlewebmastercentral.blogspot.ca/