When it comes to developing new features and looking outside the box,  propellerads will always have my vote as number one.
If you follow my posts, you'd notice that I've been a publisher with propellerads for a while and I must tell you,  it's been an awesome ride all the way.
Recently, they rolled out a new ad format called multi tag which has 3 and after formats embedded in it just as Google Adsense's Autoad serves other ad formats. 
One good thing with this is that it is not just developed to serve the ads alone, it helps increase your revenue as ads with higher cpm are shown on your blog. 
Knowing how good this could be I recently placed it on one of my blogs, see screenshots of the different formats displayed and it all happened with just a code, I no longer have to copy and paste each code separately. 
Inpage push banner format. 
Onclick popunder format
The interstitial format. 
As you can see in those screenshots, I was able to display the onclick, interstitial and in-page push ad formats on the blog with just the multi tag.

How to show multitag on your blog
I would have loved to show you this process with my own words but I figured it would be better if I give you the official guide from propellerads.

This is how the process of getting the tag will look like in the personal account:

  1. Choose MultiTag zone:

2. Name the tag (you can use the default name or create your own one).

3. Copy the code and insert it into your site’s source code (below the <body> tag).

4. All 3 ad formats will become available for your website!

Multi tag compared to other ad formats 
According to the research done by propellerads, multi tag beats interstitial in terms of revenue generation which means good news for publishers.
I've placed it on one of my blogs which is still in the hundreds in order to personally test the ad format before going live on my main blog. 
Although the format is doing better than other formats I've used before, I will provide you with before and after screenshots of my earnings at the end of this experiment as performance proof, always check back on this page to get updates on the multi tag and my experience while using it.