Remarketing is a marketing technique used by digital marketing agencies and professionals, here main goal is to reengage with the clients who were previous consumers or those people who used to visit the website but now they don't, those consumers or that particular traffic of website is contacted through targeted ads or messages, the main reason for this whole exercise is to enhance the sales by helping loyal and potential customer return back to website.
To get deep knowledge on Remarketing, you can visit the link mentioned below.
https://www.algosaga.com/blog/how-to-optimize-a-remarketing-campaign-that-delivers/