In my Activity tab under Notifications (Android app) sometimes a dot appears against the time of the post. What does this mean?

Question

First I thought it was for users who are currently online. But some posts from the same writer sometimes have dots while other posts don't, at any given time. Then I thought the dot may signify posts that I am following. But no; when I checked, posts both with and without these dots have the coloured star against the original post to indicate that I am following both these types. I know it's a very minor thing but I am curious to find out.

Answer 1

It's a seen/new mark. If you haven't seen the post the notification refers to it a has a dot

Answer 2

New notif man!