Enabling advertiser features in Google Analytics allows you to set up Google Remarketing, Google Display Network impression reporting, and DoubleClick campaign manager reporting. It also lets you track and analyze website visitors by age, interests, and gender under the demographics and interest reports.
To enable advertiser features, sign into Google Analytics, click on Admin and select the desired web property from the drop down window under Property. Once you have done this, click on Property Settings, scroll down to Advertiser Features, and turn Enable Advertiser Features to the on setting. Make sure the button under Enable Demographics and Interest Reports is also set to on if you want demographic information on your website visitors.