Hadoop versioning has always been a little confusing to me:

* 0.23.0: 11 November, 2011

* 0.22.0: 10 December, 2011

Now we have 1.0, but it's based on 0.20, not any of the more recent releases?

The 1.0 release notes are pretty useless--it's just a list of issues. Is there a summary anywhere?