There is a limit on the maximum size of a block. Depending on the size of the transactions, most blocks will hold about 4,200 transactions right now.
Thank you! That makes perfect sense. Now I feel comfortable. I knew there was a maximum size, but I only thought of that as important for keeping an attacker from flooding off all the other clients.
[quote author=DannyHamilton link=topic=148872.msg1580141#msg1580141 date=1362362258]Keep in mind that the block subsidy will continue for 136 more years, so you are getting concerned about something that probably won't happen in your lifetime. Trying to predict what technology will be like and how people will deal with the complete loss of the mining subsidy right now is kind of absurd. Can you imagine asking someone in 1877 about their predictions for technology in 2013?
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But "block subsidy" will be very small long before then, right? I'm not sure /exactly/ when it will be so small that it can't support sufficient security on its own so it was easier to ask about when it is zero.