The principle behind remarketing and retargeting is that by re-engaging your customers, who have already shown an interest in your products or services, you can provoke them to complete the desired transaction.
Although the terms remarketing and retargeting are often used interchangeably, traditionally they were defined slightly differently. Remarketing was email centred and retargeting used cookies to display ads based on the visitor interactions with the website. They both had the same goals of increasing customer engagement, conversion rates and sales through targeted visibility, so very little difference was made between the two – especially since Google remarketing should be called Google retargeting under the old definitions.