Wrote this comment on the OP (waiting for moderation):
NoSQL is not just about scale (although it can be). In my opinion the main benefit of giving up relational constraints is flexibility. Find me a relational system that can credibly do offline replication to mobile devices. Each of the options I’ve seen are full of gotchas. But if you replace the relational model with an MVCC document model, you can suddenly solve an entirely new class of problems.
NoSQL is not just about scale (although it can be). In my opinion the main benefit of giving up relational constraints is flexibility. Find me a relational system that can credibly do offline replication to mobile devices. Each of the options I’ve seen are full of gotchas. But if you replace the relational model with an MVCC document model, you can suddenly solve an entirely new class of problems.
Read about how Apache CouchDB is being used in rural Africa to bring collaborative data and web technologies to health clinics that don’t have reliable internet access: http://radar.oreilly.com/2011/03/couchdb-zambia-healthcare.h...
These same patterns are applicable to mobile connections in the 1st world.