View-Through Conversions is a type of tracking that Google makes available to advertisers to help them measure the success of their display ad campaign on the Google Display Network.
View-Through Conversions are, according to Google, what happens when a customer sees an ad, doesn’t click on it, and then later completes a conversion on your site through another channel. In this case, it is said that the ad “assisted” the conversion.
To see View-Through Conversions in AdWords (visible at the Campaign, Ad Group, Ads, and Keywords levels), you may need to include the metric by adding it to the interface via the “Customize columns” option.
One of the things that display advertising does very well is to enhance the overall value of other campaigns or channels; measuring and reporting on this important metric will allow you to access a more holistic view of your online efforts, and see the positive lifting effect of display.
As an example, let’s imagine a user who returns to your site through an organic listing, a bookmark, or a direct URL after he or she has previously seen your ad on the Google Display Network; once on your site, he or she makes a purchase. In this case, you can positively conclude that your ad did in fact have an impact on the sale process.
In conclusion, next time you run a display ad campaign on the Google Display Network, make sure you check out your report on View-Through Conversions in order to gain clearer insights into the holistic value of your display efforts.