No societal development within the past 50 years or so has been more fierce or far-reaching than that related to information and telecommunication technology. The digital technology on which it is based has penetrated every societal process and every societal activity system. It not only laid the foundations of the World Wide Web, including its derivations, but built a new global network of communication systems.

No matter how we may judge the consequences of this technical development, we cannot but concede that digital technology has entered most things in everyday life, and it increasingly determines the activity of people even if they avoid using it. In more general terms, it has become the basis of an emerging globalization process that is not only economic but cultural, not only universal but irreversible. There is nothing outside it. Reality itself has changed fundamentally.

Amazingly, most of the scholars committed to either cultural-historical psychology or activity theory do not deal with digitalization. Or at least they underestimate its revolutionary quality and so fail to prove their concepts and methodology. Clearly, when Vygotsky, Leont'ev, and Luria built the foundations of their approach, computers did not exist, and digitalization was not at stake. But does this fact justify the contemporary reserve? I am convinced that digitalization marks a twofold – methodological and theoretical – problem for activity theory, possibly the most difficult challenge it has been confronted with.