If you find any of my WordPress plugins (or any of my code for that matter) useful, and you want to know how to say thank you, here are some suggestions:
- Write a blog post about it, so that other people can find it.
- Give it a good rating.
- Pitch in to make it better! Fork it on github and send me a pull request.
- Translate my work into your language, so that more people can find it useful.