I can't make sense of the bronze badges. I've read the description on the badges page, but it doesn't seem to relate to how they are awarded. Every so often, I see my count go up, although I don't see the relationship to my activity. I have seen several posters asking their first question (rep=1), with several bronze badges. What are they?
In case anyone else has the same confusion I did, I'll answer my own question.
The badges reference page describes the various collections of badges. The collections are "question badges", "answer badges", "participation", "moderation" and "other". These collections all have bronze, silver and gold badges. It left me with the impression that separate from those badges were a set of color badges (bronze, silver, gold), that were awarded for some different purposes which were not described, and the numbers didn't seem to correlate with contributions to the site.
Answer: the participation badges are color coded into three levels of difficulty/achievement. The badge count by color shown at the top of the page refers to the number of participation badges of that color.
The "tag badges" are for accomplishments within specific tags.