Synchronous vs. Asynchronous
There are generally two major ways you can run ads:
Synchronously is how traditional ads are run; they stop the entire page from loading as the advertisement loads. These are mostly outdated, but used to be the default that most ad networks and managers would run.
In 2019, most of the internet runs asynchronous ads. That means that the ads load at the same time as the the rest of the site. Your full page can load - images, etc included, at the same time as the ads. No more waiting for the ads to go first. Mediavine adopted asynchronous ads early on, and then continued our obsession with all things site speed.
There's a reason that Mediavine ads are more than 200 times faster than our competition. Lazy Loading is IT!
The concept of lazy loading ads is relatively simple. When someone first goes to a page on a Mediavine publisher's site, we only load the advertisements that are in the first screen view, or what’s visible in your web browser, before you start to scroll.
As you begin to scroll down and we know you’re approaching a new advertisement, our script wrapper automatically detects this ahead of time and loads that ad in time before you browse to it. We do that via what we call an offset, or enough of a buffer to give the ad time to load before it appears on screen.
Lazy loading is the Google recommended way to serve 3rd party java script.
We have also recently added settings to further improve site speed for Mediavine publishers:
Optimize Ads for Mobile Pagespeed
Enabling this feature will prioritize your first screen view and optimize for Google PageSpeed Insights metrics such as Time to Interactive. By design, this feature removes ads from the first screen view on mobile to optimize mobile page speed. As a result, it may result in a short-term revenue loss, but we have found that on most sites there's an overall gain to CPM's and viewability.
Optimize Ads for Desktop Pagespeed
You can learn the details of how this feature works here. Much like the Optimize Ads for Mobile Pagespeed setting, this feature prioritizes page speed by taking ads out of the first screenview. This can include the ATF sidebar unit, along with the leaderboard unit. Removing these can lead to larger declines in revenue than the mobile option, so use caution when activating this feature.
If you are still looking to further improve desktop site speed with this feature, we recommend adjusting your first sidebar widget so that your Sidebar ATF ad is actually below the fold on your site.
To do this, you would want to place a sidebar widget (or two short widgets) at the top of the sidebar that will effectively push the first ad "below the fold" and out of the first screenview.
Please remember that if you make changes to your sidebar you will need to reach out to firstname.lastname@example.org to have your ads retargeted.