Anyone who has evaluated developer projects knows that stars are a terrible metric for a project's usefulness or popularity. So what other data is out there?
Package manager analytics
Homebrew Analytics – data on package installs and builds for the macOS and Linux distributions of the Homebrew package manager.
DockerHub image pulls – not the most useful data since this data will vary widely for CI/CD projects vs. others. Can benchmark against similar products.
Terraform Registry – Includes the number of installs for different terraform modules.
GitHub Search – Get rough estimates of project adopters by searching unique configuration file strings, either file name, e.g. docker-compose.yml or string identifier apiVersion/v1.
You can also use this to find project centrality – how often is the project used as a dependency in other projects?
The index seems to be broken and returns different answers sometimes. Better to use a scraped dataset from Google or Sourcegraph.
Visual Studio Marketplace – publishes install counts and reviews of different extensions.
Integration-Platform-as-a-Service marketplaces – Products like Zapier and other API integration platforms don't always publish numbers, but relative popularity can also give a sense of what products are often used together.
StackOverflow questions
Community members (Slack/discord/discourse)
What else did I miss? What other data do you look at for open-source projects or developer products?