First Party Data:
First Party data is information that you have collected about your audience. In advertising, first party data is often “cookie based” information, and it can include details gathered from your website analytics or CRM systems.
This is the most valuable data you can collect about your audience, because first party data provides details about existing users and customers including information about users’ past purchases and product interests. In other words you can consider first party data usage as “CRM Remarketing”.
Second Party Data:
Second Party data is basically first party data belonging to other companies who are willing to share their customers profile with you. You can purchase 2nd party data directly from the company that owns it. This kind of data plays a huge role in audience extension and targeting.
Third Party Data:
This data is provided by data aggregators (outside sources that are not the original collectors ) and is typically purchased on a large scale from publishers. The benefit of third party data is the volume you can buy, and you should also consider that data is also accessible by your competitors. Third party data is great for demographic, behavioral, and contextual targeting,
It you are just getting started and do not manage 1st party data you should start collecting information right now. In running Ad Campaigns you will probably start with 3rd party and/or 2nd party data (prospecting/targeting), and then collect info about your visitors and what they do on you site (1st party data). You own data, over time, can be effectively used by you or your media agency in “targeting” and “remarketing”, for optimizing your investment and get the most ROI.