E' tutto scritto nella pull req su git, la conversazione fra i dev che ha portato alla bocciatura del fix:
https://github.com/bitcoin/bitcoin/pull/1536coblee commented on Jun 29, 2012
This code helps with reducing dust spam. The original code will make the transaction fee become the minimum fee if any output is less than a cent. This makes it costly to send dust spam, but there's an edge case. The attacker can send a transaction with 1000 outputs of one satoshi each. The transaction size is huge but the fee is only the base fee. This fix will increase the fee by the base fee amount for each output that's less than a cent.
gavinandresen commented on Jul 2, 2012
This doesn't feel like the right fix to me.
Fixing the coin selection algorithm so it works quickly with wallets containing gazillions of tiny transactions is part of the solution. Something simple like "If there are more than X unspent outputs, don't use the fancy knapsack-problem-solver, just use the biggest-value unspent input(s) until you have enough to pay for the transaction+fee."
See
https://gist.github.com/2961409 for the direction I think will work. With the right priority algorithm (and a minimum-to-be-relayed-included threshold) I don't think a dust spam fee is needed at all.
