I have been involved with Hudson from very early days and I think my first post to Hudson's user mailing list was in early 2007 and I even wrote a little portlet that aggregated data from Hudson. I am not a kind of guy who tries to get his head around copyright issues and different OSS licenses but I always understood that
- Hudson started as Kohsuke Kawaguchi's pet project and he worked on top of his regular day job
- Kohsuke did and still does an awesome job of being involved with community and as a result got several committers and plugin developers
- Hudson got popular enough that Sun thought it deserved Kohsuke's full attention and they also started selling support for it.