You've nailed it there. Maybe I'll put 10 BTC aside, and spend the rest :-)

Now here's a thought. Suppose that I expect BTC to rise in value by 50% every year. Then, I just decide what I want my annual income to be. Suppose I want to be able to spend $20,000 per year. Here's how to do it: start with $60,000 worth of BTC, and in the first year spend $20,000 worth. The left-over $40,000 of BTC increases 50% to be worth $60,000 again. Every year I could spend $20,000 worth, forever, if the value of BTC rises at the expected rate.

Obviously, for different rates of increase and annual spending amount, the initial bitcoin amount varies.

Anyway, that's hypothetical for me. As nanotube reminded us, we have to be willing to lose it all, so I'm not going to be hoarding anywhere near that level.

If someone had a hundred thousand dollars, they could buy at least 210,000 bitcoins, which is 1% of all the bitcoins that will ever be issued. Of course it would be stupid if everyone did that, because it would mean that only 100 people could ever play with bitcoin.

On the other hand, if bitcoin grow to 210 million users, the average user will have just 0.1 BTC, and we can be ten times as wealthy as average just by hoarding one coin. Some people think bitcoin might one day need to be subdivided beyond the eighth decimal place, but even at 8 decimals each bitcoin would be worth about a million dollars in today's terms.

Obviously there's an optimum value somewhere between those two extremes. How many BTC should one aspire to hold, before freely trading the rest?

Just to show that I am working on my idea of a bitcoin animated movie, and to try out Hippch's download site, here are two fragments that I have created:

http://ubitio.us/file/download/12
01-title.mp4 - First fragment of animated bitcoin movie (no sound yet)
Opening Title

http://ubitio.us/file/download/13
02-currency.mp4 - Second fragment of animated bitcoin movie (no sound yet)
Bitcoins moving around the world

I know it's not much yet, but I've never made an animation before. The remaining fragments should come faster now that I've made good progress learning the synfig software.

The ubitio.us homepage looks clean and welcoming. Very nice.

I uploaded some files to see how it works:

http://ubitio.us/file/download/12
01-title.mp4 - First fragment of animated bitcoin movie (no sound yet)
Opening Title

http://ubitio.us/file/download/13
02-currency.mp4 - Second fragment of animated bitcoin movie (no sound yet)
Bitcoins moving around the world

On Fedora Linux I get that error if I build wxWidgets 2.9.1, but the error goes away if I build wxWidgets 2.9.0 which is available here:
http://biolpc22.york.ac.uk/pub/2.9.0/

I don't know whether that will solve the problem on Ubuntu also.

Also this:
"Which UK towns have their own currency?"

It's the best one.

It's already in place! The first 500 people to install bitcoin get BTC 0.05 absolutely free from the Bitcoin Faucet.

Sent. Thanks!

I sent 5 BTC. I'll send another 5 BTC if you rework the banner to say "Bitcoin: The currency of liberty". I think it's stronger to promote "the" currency than just "a" currency.

Even if you have all the equations supplied to you, you need to know that the source code does the same thing as the equations. So there is no getting around the need for people to study the source code.

I think an incremental approach is the only practical one here.

Specify first those parts that are (a) relatively easy to specify, and (b) for which it is particularly useful to have a specification. For everything else, just rely on the reference implementation for now.

For this incremental approach, the wiki is ideal. Some time in the future a more formal process might be considered, but for now it would just slow things down.

Here's the URL, Bruce: http://bitcoin-otc.com/

I'd love to use your service, but I'm not from the USA. Although my credit card has a customer service phone number on the back, it's not toll-free, and I'm sure they won't discuss my phone number with people who call that number.

I would like to find a verification process that is workable and is acceptable to you (e.g. mailing an original copy of my credit card statement perhaps).

The great thing about economics courses is that they can use the same exam questions every year. It's just the answers that change.

I feel a little uneasy about the "empty-string" account, because there will sometimes be user interface elements that need to display the account name, and leaving the field empty may be confusing to the end-user.

My first inclination is to suggest a reserved account name such as "default" that takes the place of the "empty-string" account. Then, a list of "balances by account" can include an entry for "default account" instead of an entry for a blankly-named account.

Obviously this will cause problems with internationalisation. So my next inclination is to suggest that some characters be excluded from a legal account name, so that those characters can be used to name the empty-string account. For example, English-language client software might present the empty-string account to the user as "(default)", but other languages could use other names enclosed by parentheses, if parentheses are not permitted to be used in a regular account name.

In any case, it should be specified which characters can be used to form an account name.

For that reason it's good to raise the difficulty before that person comes along.

The switch from CPU to GPU mining accounts for most of the recent difficulty increases.

In general, increasing difficulty is bad news for anyone generating for profit, and good news for everyone else.

Also of possible interest:
http://www.google.com/trends?q=bitcoin%2C"liberty+reserve"
http://www.google.com/trends?q=bitcoin%2Cpecunix

I understand that, but we were referring to Bitcoin Exchange. As I understand it, Bitcoin Exchange isn't a market, and the owner sets his own spread. So his spread is analogous to a fee.