Google is about to deal a small blow to some of the most annoying ads on mobile: pop-ups and interstitials. It’s not a stretch to argue that readers don’t like these ads. So Google is making a call that websites that use pop-ups and interstitials are worse search results and may rank them lower because of it.
There are a “hundreds of signals” that go into Google’s search result rankings, so it’s not like every website that uses these ads will feel pressured to remove them overnight. If a site with a pop-up still has the best information, it’s still likely to appear first. But this change ought to benefit one site over another when those two sites appear roughly equal otherwise.