1ef7220f__Guide___Salesforce_Developers__Details
[Field] InsertedById [Details] 
Type reference Properties Group, Nillable, Sort Description ID of the user who added this object to the feed. For example, if a client application migrates multiple posts and comments from another application into a feed, then the InsertedBy value is set to the ID of the logged-in user.
UserFeed | SOAP API Developer's Guide | Salesforce Developers
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