[zombio]

...And (3) force people to either create a Coinbase account or lose their money. (The post wasn't very clear, but as I understand it the receiver will get a PM linking them to Coinbase where they will need to sign up to receive their money).

I don't want to just sound cynical, so I'll try to provide a solution. Perhaps there should be an option to reply to the BitTip PM with a regular Bitcoin address where all future payments will be sent.

[barmstrong]

The micro-transactions are off-blockchain (an in-network transaction between Coinbase accounts) - unfortunately that's the only way to get them for free without any miner fees (many are very small amounts). However, if you accumulate enough tips (at least 0.01 BTC) in your Coinbase account you can then send them out of Coinbase to any other bitcoin wallet and we'll even pay the fee for you. We don't want to have any lock-in there.

It would be nice to receive your tips at an external address like you mentioned, but the miner fees could be greater than the amount you receive with such small amounts.