There are several reasons that an institution would have an IR. Some focus on preservation and guaranteed access to their intellectual works. Others create them to provide an alternative and some economic relief from the current scholarly work publishing model, and still others do it to increase the prestige of their institution. Examining the types of materials actually contained in these IR’s can help reveal whether these reasons are working and what other uses may be developing.
Again the OpenDOAR project allows access to these charts:
One of the statistics that strikes me is that multimedia items are the third most frequent type of item in US Repositories. They are growing well beyond the intial purpose of holding text-based materials. Is the software that is available up to this task?