The Pinterest tag is a piece of code that you add to your website. It lets Pinterest track visitors to your site, as well as the actions they take on your site after seeing your Pinterest ad. This means you can measure how effective your Pinterest ads are by understanding the actions people take on your website after seeing or engaging with your ad.| Pinterest Help
Google Analytics gives you the tools you need to better understand your customers. You can then use those business insights to take action, such as improving your website, creating tailored audience lists, and more.| Google Marketing Platform