Bike-sharing systems have been implemented around the world at a fast pace over the last fifteen years. There are an increasing number of books and academic papers on different aspects of bike-sharing systems, from quantitative analysis and modeling to more qualitative discussions of user behavior. Bike-sharing systems, like any other artifact, are a technological arrangement, which involves multiple technical, scientific, social, economic, and political values. Bike-sharing systems members unlock their bicycles using electronic IDs, which can be a card, a key, or cellphone code. The use of electronic-ID technologies in transportation is very common, ranging from cards used in public transportation to electronic keys or cellphone codes used to unlock bicycles and cars in sharing programs. Arguably, implementing bike-sharing systems is much cheaper than building and maintaining other urban transportation modes. Advertising is also an important source of resources to other public modes, and this is not a problem, since it is part of the business model.