What is Hook?
The hook is the opening of the content, built to interrupt scrolling. In a carousel it is the cover and the title; in a video it is the first two seconds; in a caption it is the first line before "more". A good hook promises something concrete, asks a question the person wants answered or presents an unexpected number. It has to be faithful to the rest of the content: a hook that promises and does not deliver produces low retention, and the algorithm learns fast.