The expansion of the internal market for digital content is a critical issue for the European Union. The now withdrawn Common European Sales Law was an optional instrument that was intended - amongst other things - to be a facilitator of digital content sales throughout Europe. The purpose of this thesis is to explore the potential of optional instruments for the express purpose of enhancing the internal market for digital content. The thesis analyses the evolution of regulatory methods in order to facilitate emergent contract types, leading up to the introduction of the possibility of an optional instrument (OI) for consumers and Small to Medium Enterprises (SMEs) in the form of the Common European Sales Law (CESL). Given that the CESL was officially withdrawn in 2015, the aim of this project is not to examine the minutiae of the proposal itself. Instead, this project will explore the underlying functionality of optional instruments in the field of consumer law, whether such an instrument is better suited to its task than other harmonizing systems, and where previous comparable optional legislation has proven effective. The thesis also comprehensively analyses the functionality of cross-border legislation, incorporating both the peculiarities dormant within such systems, and the economic incentive for utilizing them. The assertion being that, in order for such a system to be economically viable, it must be perceived to be so, in that its benefits are caused by such a perception. There is also a discussion of the economic models governing the proliferation of such instruments, based on similar ideas of perception. Based on the comparative analysis of the rationales for utilizing an optional instrument, the thesis concludes by highlighting how such an instrument would work with regards to digital content specifically, and whether this would be more efficient than the Draft Digital Content Directive. The theory proposed is that, if altered in such a way as to focus entirely on digital content, the aims of the legislative of the European Union can be obtained by paying close regard to the nature of digital content contracts. The conclusion is that, by modifying legislative proposals, and utilising an optional instrument to create substantial protections, the most beneficial legal system for digital content will begin to take shape. This is particularly true if the optional instrument is designed to function under Online Dispute Resolution mechanisms. Such a system would provide unity to the digital content market, and would encourage continually evolving digital content legislation.