So for "Popularity Rank on Stack Overflow" axis, I would replace the word popularity with attention. In addition to general engagement and use, a language getting more traffic/tagging there may indicate less quality documentation, more niche use (and less answers/tutorials from other sources as a result) or maybe tend to draw in (for many potential reasons) less experienced developers who are looking for active guidance or maybe the language generally has weird or non-intuitive patterns more likely to generate _wtf?_ type feelings that route you directly to stack overflow and onward to conspiracy sites from there.

The "Popularity Rank on GitHub" is probably more accurately measuring popularity in the popular sense of the word. That's especially true because the GitHub archive used for the data only offers info on public repositories and even then I'm curious to know how it reports for multi-lingual repos (does LOC win out, do repos get associated with multiple languages?).

Personally 90% of my commits over the past year have been to private repos for work. My public commits are in languages I look forward to using and learning outside my 9 to 5 because they interest and they offer a nice change up (ie PureScript and Rust lately).

I'm super stoked to see FORTRAN is riding solidly at 60% for both metrics, regardless of what those metrics truly measure. ~40 public commits in the last 24 hours! Check it out:

https://github.com/search?o=desc&p=4&q=fortran&s=updated&typ...

    Off Topic PostThought:

    Seeing JavaScript at that top corner and the amazing
    surge over the past couple years of Rust has got me
    thinking that when it comes to the art of programming
    languages, Brendan Eich is a (if not the) seminal
    artist of this time period.

    Learning JavaScript is when what Dostoevsky,
    Kierkegaard, Sartre and Camus were all trying to
    communicate really hit home for me. Meanwhile a recent
    foray into Rust is reminding me of the first time I
    read books like Tolstoy's Anna Karenina, Borge's
    Labyrinths and Steinbeck's East of Eden.

    To me it's pretty amazing that the same person has
    played pivotal roles in two languages that are both a
    joy to write and reason with and for completely
    different reasons.