But despite resilience in the structure of the network, attack vectors and vulnerabilities in the technology used by websites create conditions for fragility in the system. For instance, we found that price trackers of systemic importance use content delivery services such as Amazon S3. On February 28th, 2017 an outage on S3 buckets in northern Virginia, US, made Amazon Web Services inaccessible. Software, from web apps to smartphone applications, relying on this cloud-based storage broke, taking out a sizable part of the internet \cite{nichols}. Bitcoin reached its current price levels after rallies in May-June 2017 and December 2017, if a catastrophic event such as the AWS outage of early 2017 occurs now that bitcoin has more broad adoption among consumers and is more intertwined with the mainstream financial system, price shocks are likely.
Discussion
Not only systemically important services rely on third-party providers that may have exposures, some are inherently fragile. We found that one of the most important information services in the economy is a forum built using open source technology that is known for scalability concerns and constant security exploits; the forum operators probably never planned to reach such a large scale, so quickly. In this sense, cryptocurrency markets may be suffering from the Getting Big Too Fast problem \cite{Sterman_2007}, when market dynamics are rapid relative to capacity adjustment.
But more importantly, the cryptocurrency markets are fragile because uncertainty increases the probability of dipping below the robustness level supposedly conferred by the underlying technology of the digital assets (blockchain).
And currently, there is a deficiency of tools to understand the system dynamics in the crypto space. As a case in point, the metrics used in online trading platforms (including some that deal with cryptocurrency products, such as contracts for difference) are case specific and not generalized: the development of prospect theory's aversion to losses \cite{Liu_2014} concept for the online case, with metrics such as risk-reward ratio, win-loss holding time ratio, and win-loss ROI ratio, are not immediately portable to systemically important trading platforms with hidden exchange mechanics, such as the instant exchanges.
Here is where an adaptive approach to study the adaptive system of the cryptocurrency markets becomes instrumental to the identification and mapping the sources of risk --whether this is psychologically bound to trust-asymmetries, or more fundamental in nature, as expressed by the progression from conditions of anti-fragility to robustness to fragility. Figure 7 shows how metavariables in the tail have explanatory power for the interaction effects across different regions of complexity. Interestingly, the creation of new methodologies to understand the crypto economy, given the shortcomings of traditional economic theory, may have an unexpected effect: the advent of decentralized ledgers may also accelerate the transition from the economic equilibrium paradigm to the realm of economic complexity \cite{Bheemaiah_2017}.