Google says a View-through conversion happens when a customer sees an image or rich media ad on the Google Display Network, then later returns to your site through a bookmark an organic listing or direct URL and completes a conversion on your site. A View-through conversion is different from a click-through conversion in that a click-through conversion happens when a visitor previously clicked on an ad and then completed a conversion on your site.
In addition, because a visitor did not click on the ad but then later went to your site and converted, if you are using a cost-per-click (CPC) model for your AdWords campaign, theoretically, it did not cost you anything to receive this conversion.
View-through conversions will only occur for campaigns opted into the Google Display Network and using image ads. That being said, campaigns utilizing Remarketing are more likely to receive View-through conversions, because the visitor is already acquainted with your site and when he/she sees an image ad reminding him/her of your site’s products or services, the visitor is more likely to return to your site and convert.
Please note that conversion tracking must be in place in your AdWords account to see both View-through and click-through conversions and View-through conversions must be enabled. To enable View-through conversions, go to the “Advanced tab” underneath the “Tools and Analysis”. See screen shot below:
For more information on View-through conversions, click here.