Amazon’s strategy in the e-book market, for example, might be a case-in-point for this sort of competition. Initially, Amazon’s e-books were incompatible with most non-Kindle devices. But this lack of interoperability actually aided the company’s search for monopoly profits. Amazon e-books now can be read using Amazon’s free reader software on Android, iOS, Windows, and OS X devices. Still, Amazon e-books can only be read either on Amazon devices or through Amazon’s software.4.3.3 Autonomy, flexibility, and choice In almost all circumstances, increased levels of interoperability tend to enhance user choice and autonomy. In interoperable ecosystems, users are more likely to choose the best from among competitive and efficient options. Systems, applications, components, etc., may be tested, mixed, and matched for specific purposes. One way that interoperable systems offer choice is through application programming interfaces (APIs), which are instructions for how one application or system should talk to another.28 Twitter had an open API, which allowed anyone to write a Twitter client that could access Twitter’s underlying data. The Twitter API supported a vibrant Twitter client ecosystem, and users could switch easily between the Twitter clients of their choice. Twitter’s decision to change its API in order to capture all of the client traffic (ultimately capturing the ad revenue) has reduced user choice and nearly eliminated the availability of third-party clients.29 Users are not the only ones with greater freedom of choice when the level of interoperability increases. Consider, for instance, e-book publishers that run the risk of getting locked into a single distribution channel. If Amazon builds up a dominant market position based on a non-interoperable system, publishers will have no choice but to sell to Amazon at nearly any price it demands. By contrast, an interoperable system would lower the barriers to entry, making it difficult for Amazon to lock publishers into bad deals. In fact, it was this fear that led to a recent high-profile dispute between Amazon and publishers.30 4.3.4 Access, diversity, and openness Increased levels of interoperability can make it easier for users to access content. Creating an account can be a hurdle for users, and once they do so, they need to memorize an additional password. Single-sign-on digital ID infrastructure seeks to address both of these concerns. First, single-sign-on infrastructure allows users to log into new services using existing credentials, such as their Facebook account. This lowers the barrier to joining new services and speeds up the process. Second, because the user can log in without creating a new account, it means that user needs to remember only their single-sign on password, instead of creating a new password. “Login with Facebook” is one example of this approach, which is intended to make it easier for users to log into a variety of online services, not just Facebook.com. As more sites interoperate with a single-sign-on platform, the value to the user increases, as it reduces access barriers to online services of various sorts, including e-commerce platforms.Similarly, increased levels of interoperability can also make it easier for users to engage in commerce. The European Commission’s report on the Single Digital Market noted that a lack of interoperability, primarily at the technological and institutional levels, made it hard for consumers to purchase online goods to be shipped from one EU country to another. This was reducing access to those goods and suppressing online commerce. In response, the Commission called on the member states “to improve the interoperability of systems for cross-border delivery of goods and services….”31 In addition, there appears to be positive correlation between interoperability and “diversity.” As noted above, Twitter’s open API supported a variety of clients. Moreover, when that API was restricted, it quickly led to a decrease in the diversity of Twitter clients, with several unable to sustain their businesses following Twitter’s changes. 4.4 Potential risks and drawbacks Interoperability is not an unalloyed good. In certain instances, greater interoperability brings drawbacks. These problems tend to be highly fact-specific and are often not problems related to Trends in Telecommunication Reform 2016 107 Chapter 4