The Purdue e-Pubs repository has had over 8 million downloads.
Here's an excerpt from the announcement:
To date, every college on Purdue's West Lafayette campus has a presence in the repository. Purdue e-Pubs continues to be a central place on campus advancing the impact of scholarship at the global, national and local level. Purdue University Libraries began providing the Purdue e-Pubs service to the campus community in 2006 as a means to openly share research and scholarship in a stable, open, and citable format.
Digital Scholarship | "A Quarter-Century as an Open Access Publisher"