#1 Mobile Interstitials
Google has announced that they plan to give a search ranking penalty to sites that display full screen ads on mobile phones starting in 2017.
If you run lightbox ads or full page overlays on mobile phones you might want to discontinue that practice in 2017 to avoid the SEO penalty. Consider using a crawler instead. The crawler would not be penalized because it only covers a small percentage of the screen.
#2 Using document.write()
Another potential cause for concern is that Google Chrome will soon start blocking ads (as well as other types of scripts) for mobile users on slow 2G cellular connections if they use document.write() as discussed here.
This is probably not much of a concern for most web publishers at this time. Usage of 2G cellular is very low in the US, Canada and Europe as 3G and 4G has been widely deployed. However, in some parts of the world such as India they are still making the transition from 2G to 3G. If you have significant traffic in such regions where 2G usage is still common this may be a cause for concern.
Google has also stated that they may at a later date extend this document.write() blocking to 3G or slow wifi connections and that is what has us more concerned for the future.
The good news is that we have had a solution for eliminating document.write() usage for many years now. I'm talking about our AJAX zone code, which loads ads asynchronously and makes your site load faster. Despite these benefits many users have not switched to AJAX because earlier versions of it required a complex setup process involving a server-side proxy. However, last year we updated our AJAX zone code to eliminate the proxy requirement and it is now very simple to deploy (cut and paste).
While it isn't urgent to do anything at this time we do want to make you aware of our AJAX zone code being the more future safe option and suggest that you consider switching to it sooner rather than later to stay ahead of this situation.