We've increased the max bet from .001 to .01 for two reasons:
1) Due to the fee of .0005, players who are betting .001 (fixed) are going to lose no matter what. It is not wise to bet .001 when fees are paid.
2) There was a player recently sending tons of .001 transactions to SatoshiDice. This caused most of the delays players have experienced over the past few days. Whether it was malicious or not, it seemed smarter to just remove that tiny bet option. Any "strategy" that used small bets like that is a bad strategy unless fees were not being paid, and fees should be paid by anyone sending so many transactions.
Increasing the minimum bet is wise (just keep anything below the minimum that actually confirms as a donation). Acceptance and immediate 0-confirmation processing of the small amounts could be the root of many problems. Bitcoin requires
the minimum per-KB fee for all
transactions smaller than 0.01 BTC, whereas for 0.01 BTC transactions and larger, the minimum fee is only required if the transaction input(s) priority is too low (based on coin age and value of inputs). Sending no-fee 0.001 transactions (with a modified client) will clog up Satoshidice and everybody else's memory pools with unconfirmed transactions waiting for some pool that also doesn't follow Bitcoin rules to eventually include the free transactions, or for them to trickle down to a 'free transaction' block window, which may never happen if Bitcoin is busy.
If one were to write an informed Satoshidice-sending client seeded with enough money, it could potentially send free transactions every three blocks or sooner that comply with Bitcoin rules, through careful address management:
1. Fill address #1 with 100 BTC of gambling money,
2. Wait for two confirmations,
3. Priority of any payment from this address is now priority = sum(input_value_in_base_units * input_age)/size_in_bytes
= 100 * 100,000,000 * 2 / 300 = priority 66,666,666, which is higher than the low-priority fee requirement threshold 57,600,000. Any payment from the address is fee-free.
4. Send 0.01 bet to Satoshidice and 99.99 change to address #2,
5. If Satoshidice returns a 0.00000001 loss, discard address #1, otherwise file it away as a win address for future redemption,
6. Wait for two confirmations,
7. Priority of any payment from address #2 is then priority = 99.99 * 100,000,000 * 2 / 300 = priority 66,660,000, higher than the low-priority fee threshold 57,600,000. Any payment from address #2 is again fee-free.
8. Send 0.01 bet to Satoshidice and 99.98 change to address #3
...repeat forever and fill the blockchain for free. Load ten addresses with 100 BTC each and send 20 free transactions (or minimum two "martingales") every hour.
The same technique can be used with only one address by the client ignoring return-payment transactions when betting and only sending the large change input over and over again when it is free (along with a final "withdraw" option that sends everything except the loser dust to your main wallet).
...or someone could send 100 BTC just once to their favorite betting site that uses accounts.