What is a release?

My students are getting ready to release their open source work for the first time, with a 0.1 release.  For many of them, it's the first time they've written something that wasn't canned or otherwise a toy project.  This is, we hope, something that matters to the community, something that people will receive with interest, something to be proud of.  Today I see that Linus has a post up about doing the 2.6.27 kernel release.  I thought this was a nice discussion of what a release really is, and what it's like to do one in the open source community.