Based on your financial expertise, provide your response or viewpoint on the given financial question or topic. The response format is open.

Why are some countries' currencies “weaker”? 
The answer from littleadv perfectly explains that the mere exchange ratio doesn't say anything. Still it might be worth adding why some currencies are "weak" and some "strong". Here's the reason: To buy goods of a certain country, you have to exchange your money for currency of that country, especially when you want to buy treasuries of stocks from that country. So, if you feel that, for example, Japanese stocks are going to pick up soon, you will exchange dollars for yen so you can buy Japanese stocks. By the laws of supply and demand, this drives up the price. In contrast, if investors lose faith in a country and withdraw their funds, they will seek their luck elsewhere and thus they increase the supply of that currency. This happened most dramatically in recent time with the Icelandic Krona.