My Article

See, if you start reading this article you'll notice eventually that you lose your place, because an ad jumps in and shifts all the content from under your eyes.

Lorem ipsum dolor sit amet, consectetur adipisicing elit. Animi eaque adipisci vitae vero debitis reprehenderit modi molestiae quasi sapiente porro rerum, quos qui culpa suscipit nam cumque nesciunt ex? Dolorem!

My Article

(Slides down if layout shifts!)

This article, on the other hand (clearly a much better article), will not. The space has already been reserved at the top, and it won't shove your article out of the way when the ad gets around to arriving.

Lorem ipsum dolor sit amet, consectetur adipisicing elit. Reiciendis veniam accusantium similique officia laborum excepturi quod, porro dignissimos sint doloribus magnam accusamus eius voluptate dolorum assumenda. Similique, sequi tenetur quod!