Fieldlens posts are often active conversations, complete with questions, answers, and sometimes debates. They are an ongoing documentation of work getting done. Anyone who can view a post can react in a variety of ways - by adding pictures or videos, markups, categories, changing their status (if they are an assignee), and more.
Each addition to the post will be timestamped and indicate which Fieldlens user added it. You'll see available options at the bottom of the post on both mobile and web.