With Interest Targeting, you can expose your ads on articles or pages that are relevant to the selected interest. You can also show your ads to users who are likely to be interested in your ads.
Interest Targeting is selected as default based on the ad account’s business category and users’ content usage behavior.
Even if you have entered nothing in the interest category, once your ad gets enough number of clicks, it will be shown to target groups that might be highly interested in your ads.
You can select interest from pre-set categories or enter manually.