Part of a making a success of PPC advertising is in determining what the best ad sizes are, both from an advertiser and publisher perspective. A publisher will want to use ad sizes that generate the most amount of clicks whilst advertisers will want to gain as many impressions, clicks and conversions from choosing the best ad size. With Google releasing a report on such a matter, here are the top five ad sizes ranked in order of popularity and what this means to advertisers and publishers.
 
 

#1 300×250

The 300×250 medium rectangle is the most popular choice in PPC, roughly taking around a third of all impressions. For this reason, as a publisher, you are likely to gain the best CPC and clicks from such an advert, whilst advertisers will benefit from a lot of impressions from this, especially for image/rich media adverts.
 

#2 728×90

The horizontal leaderboard is the second most popular ad size, mainly for the large area it takes up as an advert. In general, the larger an advert is online, the more likely web users will engage with it and click onto it. Therefore, it is no surprise that such a large advert is popular in PPC, especially in the header of websites.
 

#3 160×600

The wide skyscraper advert takes the same points as the 728×90 advert, being that it is popular for its large size. For those with a sidebar, it can turn out to generate a lot of revenue, as a publisher, from sticking one so that it is effective even when scrolling down the page, to some extent. Advertisers will like larger adverts as they provide more scope to advertise their product/service.
 

#4 468×60

The banner advert is one of the originals that came with PPC, and is a great advert to stick in the header, next to the logo of a website (or above/below the content as well, for that matter). Although the 468×60, from my experience, tends to not perform anywhere as well as the above adverts, it is still a popular choice for its size to easily implement onto a website.
 

#5 120×600

The standard size skyscraper has been around for a while too, again, like the wide skyscraper, effective in the sidebar of websites.
 

Conclusion

Ultimately, if you are a publisher and looking to use PPC to make money from your website, it is a wise choice to start off using these ad sizes – if not, responsive adverts will also be a very good decision to go for.
As for advertisers, if you are looking to generate image/video/rich media adverts, then it is a good idea to stick with the most popular ad sizes, to make sure you get your advert as much visibility as possible through PPC.