Pydio (alias AjaXplorer) is a online file-sharing platform. It provides a desktop-like folder and grouping structure. It can integrate with LDAP and other authorization schemes, also provides enterprise feature and a custom syncing protocol. Pydio runs on PHP with modern browsers, but also provides clients for Android / iOS, and a Thunderbird plugin. It's distributed under a Affero GPLv3 w/ CLA, for redistribution as commercial variant.
DSpace is a digital asset managment system. It's suited for building digital repositories in educational settings, can manage text, images, videos and data sets.