Wow - thanks for the quick, extremely well crafted responses.

da2ce7 - sorry if this is an old topic; I think my confusion stems from the wiki -- it strongly implies a consensus that the size limit will be lifted.

gmaxwell - thanks; I was hadn't thought through how the blockchain would actually fork.  Yeah, you really would immediately get two completely separate chains.  Yikes.

In general I agree, the block size needs to be limited so that tx fees incentivize mining.  Overly high limits mean someone, somewhere, will mine for free, allowing people to low-ball transactions, and ruining mining incentives in general.

What I meant by the IPv4 thing is that... 1MB?  That's it?  Like 500,000 tx a day.  If only they had said 100MB, that wouldn't have really made any difference in the long run, and then millions of people could get their transaction in there every day.  Which is what I've often thought about with IP addresses: if only they'd done 6-bytes like a hardware MAC address, then maybe we wouldn't have to worry about it...

So, the wiki should be changed, right?  I'd say just reading this thread, anyone holding bitcoins, from a conservative perspective would want to avoid the chaos of a split blockchain at all costs, and not consider changing the protocol numbers.  I had been under the impression, and I think many others are, that the network (not just the currency) would in fact be scaling up enormously in the future.

As for centralization, then, the decentralization of the bitcoin transaction network will then suffer in a way.  Right now, anyone can send their bitcoins wherever they wish.  Years from now, when people are bidding against each other for space in the constantly over-crowded blockchain, no normal people will be able to make on-chain, published transactions...