In more detail
Direct messages live in a platform's inbox: Instagram DMs, X messages, LinkedIn messaging, TikTok DMs, and the like. Unlike a comment or a reply, a DM is not visible to the public, which makes it the main channel for customer questions, support, sales conversations, and creator collaborations. For brands, DMs are where a lot of real intent shows up, so response time and a consistent voice matter. Many platforms also let you trigger automated DMs from a keyword or a story reply, which is why teams treat the inbox as a workflow, not just a chat.
Example
Someone comments "price?" on your product post, so you reply publicly and also send a DM with the link and details. That private follow-up is the direct message, and handling it within an hour or two usually beats a slow reply by a wide margin.
FAQ