Greg KH, Linux kernel developer delivered a keynote in the Linux plumbing conference about the health of the ecosystem. His message was essentially that distributions that don't contribute to the ecosystem have to rely on the whims of others which is unhealthy for them. Here is an introduction the development model and some interesting statistics about the Linux kernel code. Update by TH: Rebuttals are appearing all over the web, like this one by Canonical's Matt Zimmerman ("He's refuting a claim which has, quite simply, never been made. [...] When this sort of thing happens on mailing lists, it's called trolling."), or this one by another Canonical employee, Dustin Kirkland.