When you measure your carbon footprint, you take into account your use of energy in your home (the energy required to generate the electricity, gas), the exhaust from your personal vehicle, the exhaust from your use of public transportation, and the emissions from your plane flights, among other factors. Your carbon footprint is a measure of practices and the impact on the environment. Buildings, too, have a carbon footprint. An information footprint, along the same lines, is a measure of information management practices and how the environment is impacted by those practices. The practices might be personal or corporate.
Where a carbon footprint measures direct and indirect output of greenhouse gases as a result of decisions, activities, and consumption, an information footprint can be thought of as measuring the sustainability of information practices, which includes outputs of greenhouse gases as well as financial, time, and quality of life outlays.
For example, starting with greenhouse gases, an information footprint would include, just as it would in a residence or office building, the contribution to emissions through electronic tools, such as computers, servers, and mobile phones, requiring electricity. The electricity required to run and re-charge these electronic tools is generated from coal, gas, nuclear, hydro, solar, wind, etc,. power. Information footprints can be reduced by running energy-efficient devices, using only the number of devices necessary to achieve information management goals, using renewable energy sources, and sharing equipment, such as collocating servers instead of individual servers in multiple location or streamlining inter-library loan shipments. Hardware also contributes to the footprint measure when it is either recycled or sent to a landfill.
There is a cost associated with information practices on human resources as well. Training employees on the use of a new data management tool is not cheap, either for finances or time. A product with a shallow learning curve and good enough affordances may have a lower information footprint than a product with a steep learning curve and the perfect set of features. The choice of communication channels for employees or friends impacts the information footprint in that computer mediated communication may emit larger or smaller waste as measured by the quality of interpersonal connection, sense of community building, or the energy required to learn and use a given tool. Even if the tool itself has no financial cost, the energy consumption (mental, physical, spiritual, intellectual) to engage with that tool comes at a price.
The financial measures of an information footprint, already mentioned, also include recurring software and hardware costs. Just as natural resources are limited and under stress, the decisions around what is an appropriate level of monetary investment in information tools must attend to the limited budgets of corporations and families. A municipality or an individual may decide the financial outlay for a proprietary operating system or well-branded phone may be unsustainable and instead decide to invest in lower- or no-cost alternatives.
The practices around information management itself contribute to the information footprint. Efforts to organize information assets with a controlled vocabulary, a sophisticated knowledge management sytem, and detailed metadata require planning, training, and use inputs. Those inputs depend on a finite store of energy. Those efforts can also produce emissions in the form of opportunity costs, information noise, failed information systems, and shadow information systems. Sustainability and a reduced information footprint can be aided by, for example, repurposing information, increasing transparency and access to information, and designing good enough, not necessarily perfect, systems.
All of the above rests on a philosophical foundation related to information footprints tied into values such as low impact, open source, transparency, collaborative design, good enough, investing in the community (learnings, code, best practices, training materials, sharing), and flexibility. Rather than a rigid, calculator-based information footprint measuring device, the assessment of an information footprint emerges after characterizing the set of values, inputs, outputs, and outcomes of information practices.