The ability to save content to a private collection is a feature found on social media platforms such as Instagram. The general perception is that users save content that they wish to revisit in the near future, meaning they have expressed interest in the content.
While there is no way to know the motivation behind each save, a large number of Media Saves paired with high levels of positive engagement, including likes, comments, and shares, can indicate that users enjoy and find value in your content. A high number of Media Saves is also an indicator that users are returning or revisiting your content, and potentially sharing it with their network.

