Good question... been asking myself the same... but with UnQL in the pipeline, one wonders if SQL Lite/CouchDB/MongoDB may not just take a life of their own... 
couch
-----Original Message-----
From: Mark Hahn [mailto:mark@hahnca.com] 
Sent: Thursday, December 29, 2011 10:56 PM
To: couchdb-user@apache.org
Subject: why isn't couch part of hadoop?

I noticed the rather large number of apache data solutions in hadoop and I am curious why couchdb isn't included.  Just curious.