However, there is a fairly nice way of storing older versions of documents - hold older versions as file attachments on the document. See:
http://jchrisa.net/drl/_design/sofa/_list/post/post-page?sta...
Where couchdb has some immense possibilities is in distributed applications, not only server side, but also mobile phones and browsers. Since you can write and contain an entire webapp inside of couchdb, you can technically replicate the entire app to your mobile phone, and it'd work offline or online. And if you need your app on another platform--as long as it has couchdb, you can just replicate it there.
I never see this mentioned in any overviews of comparison for couchdb.
The sticking point right now, though, is that couchdb isn't on very many mobile platforms. There has only been experiments with writing couchdb on top of HTML5's localStore, and jChris et al are working on Couchdb for android.
Keep up the good work!
CouchDB does not version, period.
As I recall, the id field is just a string. It's just common to let it do the automatic "#-hash" representation.
It's been a while since I played with CouchDB though, so I could be off.
If you need versioned records, you are likely better off identifying your versioning requirements and building to those than trying to piggyback off of something else poorly suited.
Just my $0.02 :)
K.