OK, revise the question - if the connection to the rest of the world was spotty, say, once a week, instead of non-existent, how would that change things?
My reason for asking this is I am developing a product for deployment in the Third World that Bitcoin is a great fit for, but it must be able to function with only intermittent access to the blockchain and support 50-100 users.
Besides spending an hour or so (on a fast connection) to download the last week's worth of transactions anyone on the island would also have to wait a week to truly see their transactions confirmed. If they mined on their own, then they would create transactions for those coins, sure, but as soon as they hooked back up to the mainland, all of those transactions would be reversed/deleted, and they would have to wait until those transactions were processed by a miner on the mainland (or by them while they still had the connection to the mainland).
So:
- They couldn't mine coins, because they would be reversed when connected to the mainland.
- They couldn't send transactions, unless they didn't mind waiting for a week for each one to be confirmed and for the person receiving them to be able to spend them again.
Really, I think it'd be a good idea to create a local version of Bitcoin (not even a fork, just a start-from-block-1 Bitcoin Island Edition), and let them mine away. They'll end up setting their own values for the coins as appropriate, and they would never have to connect to the mainland. Perhaps there may arise some demand for these Island coins from people who visit the island (?), so an exchange could be created where island people could trade their island coins for regular Bitcoins, and use them on the mainland, etc.