Earning the attention of an audience is one of the toughest jobs in marketing.
The best way to do this is with a marketing hook.
A hook is an angle used in content and advertising that grabs attention, creates interest and makes an audience receptive to your messages.
In other words, it gets your foot in the door.
BTW: Do not confuse a HOOK with a USP. Unique Selling Points belong to a product/service. Hooks belong to marketing and advertising content.