About a month ago, Google announced that it would begin using mobile-friendliness as a ranking signal starting on April 21. This gave webmasters some time to prepare to avoid potentially devastating effects in search results. This is a major update considering that people are only searching Google more frequently from their mobile devices.

Google algorithm changes have ruined businesses in the past, so it was good of the company to give some warning on this one. They don’t always do that. It’s going to be interesting to see what sites end up taking a substantial hit when the time comes. Most well-known sites should be ready.

Ricardo at DigiDay writes, “Top publishers, for the most part, appear prepared for the change. Out of the U.S. publishers in comScore’s top-100 rankings, the vast majority of them — including About.com, The New York Times and The Wall Street Journal, pass Google’s mobile-friendly test.”

He notes that sites like Mail Online and Weather.com have homepages that don’t pass Googles mobile-friendly test, but also that Mail Online’s article pages do. This is probably enough for the site to not take major it. As we recently learned, the update works on a page-by-page basis as opposed to a side-wide one.

Googles’ Gary Illyes recently said as much at the Search Marketing Expo. He also said the signal would run in real time. If only parts of your site are mobile-friendly, the parts that aren’t shouldn’t hurt them. This eases the burden on webmasters who ay have thought they needed to have their entire sites mobile-friendly by the algorithm update’s launch date. It’s still a good idea, of course, but as long as you take care of your most important pages, you’ll probably be fine.

On Tuesday, Google hosted a live Q&A Session to answer questions about the mobile-friendly ranking change. Here’s the whole thing if you want to spend an hour of your time on it:

Barry Schwartz at Search Engine Roundtable has been pulling out some nuggets that are helpful to know. For example, while this is pretty much common sense, may be helpful to see it confirmed: If your site carries the “mobile-friendly” label in Google’s search results (it’s been displaying this label since last year), you shouldn’t have anything to worry about. The quote from the video:

Take out your phone, look up your web site. See if there is a gray mobile friendly label in your description snippet. If it is in the search results, if you see it, that means that Google understands that your site is mobile friendly and if you don’t see it then we don’t see that your site is mobile friendly or your is not mobile friendly.

Another helpful thing to know is that information in the mobile usability report can sometimes be delayed. From the video:

It might not be the most updated information. So if you did change your site and you want to see if we detected it, run it through the mobile friendly test. The mobile usability report will catch up when it crawls.

One more important point Google clarified in the video is that there aren’t different degrees of mobile-friendliness when it comes to the ranking signal. Pages will either be seen as mobile-friendly or not. From the video:

You either have a mobile friendly page or not. It is based on the criteria we mentioned earlier, which are small font sizes, your tap targets/links to your buttons are too close together, readable content and your viewpoint. So if you have all of those and your site is mobile friendly then you benefit from the ranking change.

As they went on to say, Google still has over 200 different ranking factors, so the mobile-friendly signal is still just one of them, and will work in conjunction with everything else.

While the algorithm update will begin on April 21, Google says it could take a couple of days to a week to fully roll out.

There are a variety of factors that go into making your pages mobile-friendly. If your site isn’t in good shape, you’re going to want to make friends with Google’s mobile SEO guide, and of course the mobile friendly test. You can get a summary of both of these here.

Google has also been giving tips on things you’ll want to avoid. More on that here.

Don’t forget, the mobile-friendly signal is only one of two mobile-related algorithm changes Google announced. The other one has already gone into effect, and looks at content within apps. If you use app indexing for Android apps, your content may show up higher in search results for signed in users who have your app installed. More on getting set up for that here.

Google also recently announced another ranking signal that isn’t necessarily mobile-related. The company said earlier this month that it would launch a ranking adjustment to better address doorway pages.

Image via Google