In most of my social groups, “pop” is equivalent to what you describe using “backthumb” for. This started with the programmers, who also use “push” when deliberately introducing a new temporary topic, and reached fixation.
In my experience “pop” is connotationally very different from how the Boston rationalists “backthumb”; “backthumb” contains a value judgement that the nascent conversation branch would be a poor use of time even if there is much that could be said about it, while “pop” is primarily used to return to a previous topic after a conversation branch has exhausted itself naturally.
In most of my social groups, “pop” is equivalent to what you describe using “backthumb” for. This started with the programmers, who also use “push” when deliberately introducing a new temporary topic, and reached fixation.
In my experience “pop” is connotationally very different from how the Boston rationalists “backthumb”; “backthumb” contains a value judgement that the nascent conversation branch would be a poor use of time even if there is much that could be said about it, while “pop” is primarily used to return to a previous topic after a conversation branch has exhausted itself naturally.