In the days leading to the outbreak of the COVID-19 pandemic, open innovations in the form of the deployment of digital marketing tools in the management portfolio were an option; in a time of forced closing of economies, they suddenly became a necessity. The aim of the comprehensive research, in which the presented study is prepared, is to describe the changes in e-consumer behavior that occurred in the market during the COVID-19 pandemic. The presented study examines the seasonal and regional specifics that characterize the markets of Central and Eastern Europe. In a sample of almost 14,000,000 Facebook users, the user interactions with ten selected representatives of the e-commerce sector were recorded daily during the 2020/2021 Christmas season lasting 49 days. By analyzing the nature and timing of interactions, it was possible to identify the geographical specifics of e-consumer behavior, as well as basic seasonality indicators based on a comparison with the reference period of the first half of 2020. The synthesis of the findings provided a knowledge base for compiling a preliminary version of the model of the COVID-19 pandemic impact on e-consumer behavior. In terms of changes in e-consumer behavior, it can be stated that the step change in e-behavior patterns caused by the pandemic merges with pre-pandemic behavior patterns. In general, it can be stated that the evolutionary process of the transition from offline to online the COVID-19 pandemic appears to be a significant acceleration factor of inevitable changes.