yup I know what hbase is, we used it at my previous job (but I recall stuff like "reimplementation of hbase in bash"[1] being insightful, it was not a great experience though I'm sure it matured a lot by now)
Thanks a lot for the conference video, but even this mostly describes their "well known" scribe/log analysis infrastructure, and does not get into how the new stuff gets integrated with hbase.
Here is a video from the recent Hadoop World conference, where Jonathan Gray from Facebook speaks about their experiences with HBase:
http://vimeo.com/16350544