OP author here: the rivalries there are directional, "if you liked X, you probably disliked Y", but not vice versa. (One thing I find interesting is that most rivalries really are directional: you see git users disliking svn, but not svn users disliking git).

Perhaps there's a way I could make that clearer in the post!

> OP author here: the rivalries there are directional, "if you liked X, you probably disliked Y", but not vice versa. (One thing I find interesting is that most rivalries really are directional: you see git users disliking svn, but not svn users disliking git).

Awesome, thank you! I agree that the direction of the rivalry is an interesting part of it.

I just noticed that "backend : frontend" and "frontend : backend" both appear on the chart, which implicitly answered my question.

Perhaps another sentence or two that highlights this would help readers understand the directional nature of the chart. For example: These rivalries are directional, which demonstrates how rivalries are often asymmetrical. For example, as seen in the results chart, those who like backend have more distaste for frontend than vice-versa.

The ":" implies bidirectionality (or at least, non-directionality), you could clarify it in the graph by replacing ":" with "dislikes" or "->".

As a coder, : is pretty directional in my head.

A greater than sign would be explanatory tho.

Yeah. I first observed this and was confused because the phi coefficient should be symmetric---I understood what's going on only after proof-reading the description (again).

backend : frontend and the reverse are both present, that implies unidirectional relationship.

I like how illustrative it is in the general context of rivalries: I observed that people are most negative towards their neighbors, as opposed to those who are very different.

Perhaps it's because similar agents need to compete for similar resources?