Ad targeting, as defined by Wikipedia, is "a display advertising technique used by online advertisers to reclaim consumers who visit retail sites and leave without making a purchase. This serves as a complement to search, SEO and other marketing campaign tactics."
Display ads, by design, are used to attract more viewers to your site through various sites on the Internet.
Retargeting ads will function like this but in a totally different audience. Basically, targeting is aimed at people who have seen your ad and are quite familiar with your brand.
Re-targeting collects the most basic information from you, via cookies in your browser and uses it to display ads on every page that you open on the Internet as long as they are connected to the retargeting system. Each ad will be unique for each browser depending on what they see on the retailer's site.
Re-targeting and Screen Advertisements
As the name implies, retargeting is about targeting people who have seen your ad before and have visited your site.
This means that the scheme only works if there are enough people who have visited your site. This also means that you have to use another form of display ad to direct these people to your site.
Using retargeting with the AdWord Campaign and other pay-per-click ad schemes can improve the results of both marketing strategies, giving you a huge return on investment.
With retargeting, you are given the option to choose ads that can be seen by visitors based on what they have seen on a particular page on your website.