While currencies are just one of several possible application areas of blockchain technology, they are by far the most popular. Likewise, while Bitcoin is just one of many currencies implemented via a blockchain, it is by far the most well-known. Many recent initiatives have focussed upon the more wide-ranging possibilities of blockchain technology, but it is rare to find any mainstream discussion of blockchain without some reference to Bitcoin or, minimally, to blockchain-enabled currencies. Since currency applications dominate discussions about blockchain and represent the most mature and well-known applications, they have great influence upon the development of blockchain technologies more broadly. Here follows a brief discussion of how blockchain applications for currencies work and some of their implications. However, since there are already several accessible guides and discussion pieces on this topic, the focus will be on how Bitcoin's dominance of the blockchain field could affect wider development of the technology and other applications of distributed ledgers. \cite{Clack_2018}

TAX TREATMENT OF VIRTUAL CURRENCIES

The IRS and state tax authorities are the primary agencies with jurisdiction over blockchain tax concerns, except where criminal conduct is suspected (see below Criminal Implications). While the IRS issued a notice several years ago indicating that it will treat virtual currency as property rather than currency for tax purposes, it has provided little additional guidance (see IRS Notice 2014-21, at A-7 (Apr. 14, 2014), available at irs.gov). The IRS assumes that once virtual currency is characterized as property, normal tax consequences flow from that. Although this characterization answers many questions, numerous questions remain unaddressed. For example, the appropriate tax treatment of a token with equity-like or debt-like features, or a virtual currency that undergoes a fork (that is, when the blockchain splits into two branches), remains uncertain.