Google has decided that a site which fails on a phone should rank lower, and a good part of the industry is upset about it.
I understand the panic, though I don't quite share it. We had years of warning. Mobile first was never a secret. It is easy to feel caught out when a thing you were told about for a long time finally arrives, and I don't think Google has done much here but stop pretending along with the rest of us.
I say that gently, because I have been on the wrong side of exactly this kind of shortcut.
Years ago a business partner and I ran a small studio called versionthree. There was a trick going around then, the sort of thing everyone knew and nobody said too loudly. You could put keywords on a page as white text on a white background. Invisible to a person, irresistible to a search engine. So we did it. On our own site. For our own studio.
We ranked beautifully. And then we didn't exist. Blacklisted, gone, so completely that we couldn't find ourselves. It was one of the more instructive weeks I have had.
The lesson wasn't that we got caught. It was that we had been building for the machine instead of the person, and the machine notices eventually, because the machine is only ever trying to approximate the person. Every shortcut is a bet that the algorithm won't catch up. It always does.
So build the thing that actually serves someone holding a phone. Not because Google now says you must, but because Google is only naming something that was already true.