The asterisk has long been used to highlight exceptions or to call attention to a footnote or annotation. For example, a home run record that was influenced by an extended baseball season was noted with an asterisk. This mark is also used to call out legal terms or extended information on a topic.
I think we should be using an asterisk in our conversations about Industry 4.0. This blog explains why I chose an asterisk instead of some other mark in my description of Industry 4.0*.