The web offers a ubiquitous platform for commercial and information-sharing activities, which are realized by a broad spectrum of web systems. Not surprisingly, triggered by lawsuits, many legal aspects impacting web systems have emerged over time and they should be a concern for web systems operators, users and researchers. This paper identifies prominent legal issues relating to web systems access, content, design and code: copyright, patents, contracts, trespass, and others. Based on the identified issues we offer a number of observations on how the legal landscape has been shifting, on the role of contracts, and on the law's impact on case study research.