First party data is data that you collect on your own website and your own systems. This can include your website, CRM, POS, customer service data, in-store tracking, etc. For example, using a tool like Google Tag Manager you can create custom “events” on your website that tell you about user behavior on your site. Using this you can track how far down a page someone scrolls, whether they start a form and then don’t submit it, if they watch a video and to what point, etc. This data can then be used to personalize and customize both the web experience someone has when they return to the website and the ads that they see in the future. It can also give you invaluable insight about how good of a job your ads and landing pages are doing at converting your audience into customers.