In this section, we will study the various attempts to classify business models in literature, pausing to look at the factors that each author has considered crucial for the grouping of the different models. In addition to more theoretical approaches, we will look at those based on observing existing businesses in a more qualitative way and a quantitative methodology for the classification of business models in the context of the FLOSSmetrics project. Lastly, we will propose a taxonomy of our own that combines all of the proposals discussed.