Jonathan Ellisâ€™ started up a storm when he posted an entry about CouchDB about 6 months ago. He questioned some of CouchDBâ€™s claims and made an attempt to warn users who donâ€™t understand practical issues around CoughDB very well.
After reading his post and some comments, it looked like he was specifically concerned about CouchDBâ€™s ability to distribute/scale a growing database automatically.
Its a good read if you are curious. He has stopped accepting comments on his blog, but that shouldnâ€™t stop you from commenting here.
As Jan pointed out in the comments Jonathan is assuming â€œdistributedâ€ means â€œauto-scalingâ€ which is not true.