Well, according to Wikipedia it started out as the Spanish Peso (pre-dating the US Dollar), so it's no wonder that countries that use the Peso (like mine) use that sign.

http://en.wikipedia.org/wiki/Dollar_sign#Origin

BTW the character intending to be the Bitcoin Logo shows up as a box for me, I could only see it on the original link's page.

My experience (from living in such countries) is that indeed people prefix with the country to make it unambiguous. I.e. AU$, CA$, etc.

I generally find this to be extremely confusing.

Really? Why?

If you're in a country where a dollar is used, and you see $, you assume it's the local dollar. If it's not, they'll use something to denote the currency. If it's the internet, same thing, you see if the company is Canadian, or American, or whathaveyou.

And what should they use in Thailand for Bitcoin?

That has any significance to my comment... how?

My comment was very specifically showing how using the dollar sign in a country where a local currency which is also a dollar (ie. Canada) but not USD is not confusing, because you have local context. You know you're not talking about the US Dollar, because the local currency takes precedence.

And, as winthrowe replied, what would happen is you add a currency denotation after the value, such as CAD, USD, AUD, etc. It's already done all over the world.

Why not ฿ and ฿BTC much like we do $ and $USD here in Canada?