At DANS, we host a national portal for scientific information, NARCIS. Within the FREYA project, we have worked on a NARCIS PID Graph that uses PIDs to enrich the information we can display in our portal.
If you are interested, you can read more about it in this blog post: https://www.project-freya.eu/en/blogs/blogs/pid-graph-enriches-information-in-dutch-research-portal-narcis