I am researching indicators of a software's popularity and good qualities. How do you determine that some piece of software is good and popular?

Think in terms of how you might decide which framework you should use for a long-term project. I don't want to bias you too much, but here are some examples (which may not always be applicable). Feel free to go a bit outside the box.

- great documentation

- well-commented code

- number of contributors and stars on GitHub

- references on Hacker News, Stack Exchange and relevant subreddits

- lots of videos on YouTube

- logo and branding

- conferences and workshops

- mentions in skills and experience on LinkedIn

- mentions in job offers

- frequency of searches in Google Trends

tl;dr: How would you assess a software's popularity and good quality?