$8 billion is not the total paid for every bitcoin in existence. Ask the people who bought at $1. This is what I'm interested in.

Good answer, this is what I was looking for. Thank you.

But what price did you buy it at? Am I paying more than that? If so, money goes into the system.

Thanks, that's a useful starting point. We're looking at an orders-of-magnitude difference, then. Rather than the train passenger theory of "if ten times as many people adopt bitcoins the price will go up ten times."

I disagree. Someone buys and the price rises. Sell and it drops. Buy and sell and it stays the same. Marlet cap of $8 bn does not mean $8 bn investment.
I bet it has something to do with calculus.

Simple question, possibly a complicated answer. One for the economists?
Bitcoin's "market cap" is currently around $8 billion = $640/btc x 12.5 million btc in existence.
However, this does NOT mean that $8 billion has been poured into bitcoin. Almost all were purchased at lower prices (or mined). Many coins were bought at a very low price. As more were bought, the price rose, to where it is now. Basic supply and demand.
My question is: roughly what is the total amount of money that was spent in pushing the price up to where it is now? I imagine there's some sort of exponential graph or a standard model that illustrates this, but I've no idea what it would be.
I think this is relevant because it gives an indication of how much the price would rise given further investment, or how much it would fall when people sold.
That would give a much better metric of long-term prospects than I've seen just about anywhere else. It might allow us to say, If xx corporate investor came on board with $yy million, where would the price go?
Or we could just keep talking about the magic train that's going to take us to the moon...

You may have more than one problem here. One is that UK banks hate bitcoin. You need to find one that won't withdraw its services without notice. bit121 could go the way of its predecessors now. That's just too much uncertainty: they can kill your business at a stroke.
Another issue is that you have to get people to use the bank you choose, depending on the nature of your business. Bitstamp uses a Slovenian bank, but the UK banks (which your customers will presumably use?) get charged for making SEPA transfers, and they get charged a terrible exchange rate. Buy one bitcoin on Bitstamp from the UK and you could effectively pay 6-7% fees as a result. No one in the UK is going to use that service where small amounts of money are involved.
I've looked into this, a little, because I had an idea for a simple site that would allow people to buy and sell coins. Not exactly an exchange, but not like the sites currently doing that in the UK either. Basically something that is appropriate to where the UK is at in terms of bitcoin adoption. (Sadly, having come up with what I think is a viable idea, I don't have the programming skills to make it happen.) Of course you have to use the banks in some form, but there are various ways of doing that, some safer than others.
Depending on what you need them for, you may also run into issues of APIs etc, which they may or may not have/make available to you.
Feel free to PM me if there are more details you don't want to give on a public thread. I'm no expert but I may have one or two ideas if they would be useful.

That's what I figure. Fundamentals (i.e. the extent of bitcoin adoption and use by business) is going to drive the price much more from now on. Speculative money less so after Gox. Not a bad thing: bitcoin needed the reality check to become more respectable.

It's academic anyway, since today is looking Quite Bearish. Sorry to be the bear of bad news.

Can't be a bad thing.
Doesn't look like the story came to anything, though the real Satoshi apparently surfacing is what's really intriguing here.
And despite the maxim, the fake Satoshi does seem to have got a free lunch out of it.

You'd think so. But the banks hate bitcoin. Just about every exchange that has been opened here has been hamstrung when banks withdraw facilities. bit121 was the latest - happened in the last couple of weeks. No surprise that Stamp use a Slovenian bank.
Result: are you sold on using a bank at all, or are there alternatives?

This story has really been picked up in the last couple of hours. Nothing much new, just recycled, even by 'reputable' (yeah, I know what an oxymoron is) news outlets. Sucks for Mr D. Nakamoto. If it's not him I hope that journalist gets slapped with a lawsuit.
Supply/demand. Dump anything on the market and the price goes down. Dump a lot and it drops a lot. Dump a very lot and maybe there's enough to depress the price for quite a while.
No reason why Satoshi would do this, or why any major bitcoin holder would do this. You might as well ask what would happen if xx pension fund dumped all their stock of yy company.

If the cat's out of the bag, that's the least of his worries.
Got to wonder, though, if he's lost the key (or chucked it away, way back when). I always wondered what Satoshi was planning to do with his ~$1 billion haul of coins, and why he hadn't touched them - even to move them to another address - for so long.

As so many people on these forums do not appreciate, "Past performance is no guarantee of future performance".
I've never died yet. Why would someone think I'm likely to die in the future?
Satoshi has c. 1m coins. He may or may not spend any or all of them. I imagine Satoshi himself is the only person properly qualified to know whether he ever will. In my mind, becoming the potential target of robbery, extortion, crank calls, begging letters, kidnapping and unwanted press intrusion makes him more likely to spend them than before.
And he doesn't seem to care much about his creation, if it even is him.

Identity gives information about motivation.
Ultimately, it's just supply and demand. If people thing Satoshi is likely to sell his half-billion-dollar haul of coins, that's not good. If they think he's lost the keys, that is (though not great for him).
If they decide he's working for The Man, that's just rude.

Well, yes. Clearly, one does not simply create a groundbreaking global, decentralised, secure payment protocol, entirely outside of the control of banks and governments, simply because you are upset that Hornby spares are costing you too much.
I feel the need for a meme.

In all fairness, there was a good amount of circumstantial evidence. And I really appreciated the incidental touches, like him enjoying toy trains. They make it far less likely it's all fake.
What I really love, though, is that it wasn't some NSA project or a secretive group of anarcho-libertarians. The motivation was that some guy got annoyed because it cost too much to buy toy train spares from England.

Another stupid altcoin? So bitcoin is now an altcoin derived from itself?

Or try Googling it...

Well I for one am furious that the shadowy creator of bitcoin, known only by the cryptic identity Satoshi Nakamoto - which was CLEARLY a pseudonym since that's the only thing about him people agree on - actually turned out to be called Satoshi Nakamoto in real life.

This clearly means the protocol is insecure and even if it wasn't I'm still selling all my coins in protest.