Brands and advertisers can access your ad inventory through any large ad exchange or supply-side platform (SSP). This allows them to easily target their spend to your site (and other sites with Raptive, if they’re interested). In order to have their ad appear on your site, they have to bid higher than any other brand.
This means the entire process is totally hands-off for you (you don’t need to manage the relationship or keep track of campaign parameters), and you’re always making as much as possible for each ad impression on your site. If a brand contacts you about ad placements, that’s the easiest answer!