  Humans acquire and accumulate knowledge through language usage and eagerly
exchange their knowledge for advancement. Although geographical barriers had
previously limited communication, the emergence of information technology has
opened new avenues for knowledge exchange. However, it is unclear which
communication pathway is dominant in the 21st century. Here, we explore the
dominant path of knowledge diffusion in the 21st century using Wikipedia, the
largest communal dataset. We evaluate the similarity of shared knowledge
between population groups, distinguished based on their language usage. When
population groups are more engaged with each other, their knowledge structure
is more similar, where engagement is indicated by socioeconomic connections,
such as cultural, linguistic, and historical features. Moreover, geographical
proximity is no longer a critical requirement for knowledge dissemination.
Furthermore, we integrate our data into a mechanistic model to better
understand the underlying mechanism and suggest that the knowledge "Silk Road"
of the 21st century is based online.
