What is Broadcast channel?
A broadcast channel is an Instagram feature where the account sends messages, photos, videos and polls to everyone who subscribed, inside the DMs. Only the channel owner writes; subscribers react with emoji and vote in polls. It works like a public broadcast list: whoever joins gets a notification for each message, which gives far more reach than the feed. It differs from API broadcasts, which send individual messages to opted-in contacts and allow personalizing and segmenting.