Google: The Mobile-Friendly Ranking Factor Runs In Real-Time & Is On A Page-By-Page Basis

Google tells us that the mobile-friendly algorithm launching in about a month is on a page-by-page basis and runs in real-time, which eases the concerns of many webmasters.

Google announced last week that a new mobile-friendly ranking factor will be added to the mobile search algorithm on April 21, 2015. At SMX West yesterday, Google’s Gary Illyes answered some questions around this new ranking factor, explaining that the ranking factor is run in real time and that it works on a page-by-page basis.

Real-Time Search Algorithms

On the Mobile SEO panel that I moderated, we asked Gary when do webmasters need to get their sites mobile-friendly for them not to be impacted by the April 21st launch. Gary explained that the algorithm runs in real-time, so technically, you can do it any day, and as soon as Google picks up on the change, the site will start to benefit from the new mobile-friendly algorithm change.
By real-time, I believe this means that once Google crawls the page again, it will immediately be labeled as mobile-friendly and immediately benefit from the algorithm. If your pages are slow to be indexed because they are rarely updated, then it is important to go mobile-friendly sooner.
Google did not clarify if it was real-time in the sense that as soon as Google crawls and indexes the mobile-friendly page, or real-time in the sense that it checks when the query is entered into the search box. I would have to assume it is when Google crawls and indexes the page. And depending on how often Google crawls and indexes your web pages, you will need to time it so you can get all your pages mobile-friendly by that April 21st date.

Runs On A Page-By-Page Basis

Gary Illyes also confirmed that this algorithm is run on a page-by-page basis. So if you have 10 web pages on your web site and 5 of them are mobile-friendly and 5 are not, then only the pages that are mobile-friendly will benefit.
Google initially would not confirm if the mobile-friendly algorithm is site-wide or page-by-page, so having this known is important for webmasters. Many websites have sub-sections or specialized pages that would be hard to make mobile-friendly, so webmasters do not need to fret about going 100% mobile-friendly by April 21st.
Of course, going mobile-friendly for all your pages is important as mobile user growth explodes, but you can make a decision on a page-by-page basis if the conversion process is complex on your content management system.