Any system in which growth is proportional to the principal, added to that principal, and then repeated.
Content creation and audience building is a compound growth system. This is beause the value of new content and new audience members increases in proportion to the existing principal of content or audience. It also explains why content creation takes so long to produce any income - compound growth is most impactful at the end.
If each piece of content produces a fixed value per view, early content with a small audience and a small content library produces low value. There are several reasons for this:
Conversely, content created in a more mature publication creates phenomenal value: