Google planned to punish non-mobile-friendly websites starting in April, 2015. Turns out they did.

On April 21, Google warned that it was going to roll out a change to its search algorithm that would favor mobile-friendly websites over non-mobile-friendly ones when people conduct searches on mobile devices. This change could negatively affect one company over its competitor. Leading up to this so-called “Mobilegeddon,” web developers (and their clients) were in something of a frenzy. April 21 came and went, however, and initial reports found little impact.

Until now, that is.

A new report from Adobe Systems reveals that traffic to non-mobile-friendly sites fell 12% in the two months after the changes took effect, relative to mobile-friendly sites. The most striking impact hit over Memorial Day weekend in late May, when more people used portable devices than personal computers to conduct searches. “Mobilegeddon fears have come true,” said Tamara Gaffney, an Adobe analyst. The Adobe report reveals that smaller companies were the hardest hit, as they have struggled to keep up with Google’s new mobile standards.