Instagram - is rolling out a feature that provides a similar experience from other social channels. In a Twitter post, Instagram announced the rollout of pinned comments to all users. “Today we’re rolling out pinned comments everywhere. That means you can pin a few comments to the top of your feed post and better manage the conversation.”

Instagram Releases: Pinned Comments
Instagram / Twitter

Users are allowed only three pinned comments per postHow To use: Users simply swipe left on a comment and click the pin icon to propel it to the top. Once pinned, the user who posted the comment will be notified.