Sentence:  The <WSD>"primum mobile</WSD>" and main engine of the Information Society in Europe, NDS [new digital services] have been the focus of urgent attention among European Institutions and Member States who are suddenly confronted with the arduous task of transitioning regulations conceived in a very different analogue environment. 
Meaning of the word marked with <WSD> tags:  The person or thing that is the main impetus for some action; a driving force.