Some interesting metrics relating to bugzilla.mozilla.org, courtesy of justdave:
| Metric | Ever | Last 30 Days |
|---|---|---|
| Logged In Users | 414,284 | 7,153 |
| Users Who Changed A Bug | 4,053 | |
| Bug Reports | 654,360 | 6,939 |
| Unique Bug Reporters | 144,950 | 2,126 |
| Unique Attachment Uploaders | 29,427 | |
| Unique Patch Submitters | 5,265 | 370 |
| Unique Commenters | 180,927 | 3,616 |
| Comments | 5,446,473 | 57,182 |