一，投资永恒&稀有的信息，蛮有意思。
二，PPT最后一页对比特币的估值采用的好像是费雪公式。先抛开那些假定的参数，只看模型，我感觉不太对劲（整个过程没有提到流通速率）
1，黑市电子货币流通量318bn，没有看出是怎么乘出来的（看起来，这个318bn跟实际值也没关系，2018年1月21日，加密货币总市值（美元）5930亿 ，比特币2057亿）
2，用“电子货币流通量”318bn 乘以50%，得到“btc总市值”， 这两个数字好像不是同一回事/同一个单位？
点击查看图片的原文（BTC的估值模型）
三，对于underground GDP的预估。这个数字蛮大的，具体见下文。但是其中多少是使用加密货币来完成的不好说。（跟据我看的一些杂乱的信息，直观感觉现在还很低。但是由于加密货币做这些事情成本低效率高，将会增长很快）
underground economy 定义
The underground economy refers to illegal economic activity. Transactions in the underground economy are illegal either because the good or service being traded is illegal or because an otherwise licit transaction does not comply with government reporting requirements. An example of the first category includes drugs and prostitution in most jurisdictions. An example of the second category includes untaxed labor and sales and the smuggling of goods to avoid duties. The underground economy is also referred to as the shadow economy, black market (not gray market) and the informal economy.
GDP占比：
According to estimates, the American underground economy was approximately 8% of GDP, or $1 trillion, in 2009.（Estimates of the size of the underground economy in the United States range between 7 and 11% of the total economy as of 2016.） The OECD average underground economy was approximately 20% from 1999 to 2010. France underground economy was closer to 15% while Mexico's was closer to 30%.
（备注：The OECD was established on Dec. 14, 1960, by 18 European nations plus the United States and Canada. It has expanded over time to include members from South America and the Asia-Pacific region. It includes most of the highly developed economies.）
