This shows the flow of items into DPLA hubs from their content providers. I discovered 1,309 total providers, but not every provider is represented. If I couldn't determine a hub or the provider name was nonsensical, such as edm:dataProvider, it was left out. There are some interesting linkages, such as partners that provide content to multiple hubs.
Link width is a measure of flow into a hub. Hover over a link to see how many items were contributed. Drag the nodes around to reorder them. There are clearly some parsing issues here. Metadata isn't always consistent between providers. Notice that for some reason the Mountain West Digital Library seems to have no providers that contributed at least 100 items. Nevertheless, any errors are my own. I'm happy to correct inconsistencies if hubs/providers have the actual item counts. I had initially included the flow from hubs into the DPLA, but the item counts overwhelmed the counts from providers into hub, making the whole thing a bit of a mess. If you'd like to see the flow from hubs into the DPLA click here.