Pleiades is an international research community, devoted to the study of ancient geography, organized by the Ancient World Mapping Center at the University of North Carolina at Chapel Hill, U.S.A. The Pleiades project is open and aims at bringing together a global community of scholars, students and enthusiasts.
Their about
page says:
The Pleiades web portal is being built atop the open-source Plone Content Management System, with the addition of a number of plugin components (Plone "Products"). All modifications and special-purpose plugins developed by the Pleiades Community will be released to the public for free re-use under compatible, open-source licensing.
It's encouraging to see that such a large project benefits from free software and, at the same time, gives back to the community.
SIMILE is a joint project conducted by the W3C, MIT Libraries, and MIT CSAIL. SIMILE seeks to enhance inter-operability among digital assets, schemata/vocabularies/ontologies, metadata, and services. A key challenge is that the collections which must inter-operate are often distributed across individual, community, and institutional stores. We seek to be able to provide end-user services by drawing upon the assets, schemata/vocabularies/ontologies, and metadata held in such stores. SIMILE will leverage and extend DSpace, enhancing its support for arbitrary schemata and metadata, primarily though the application of RDF and semantic web techniques. The project also aims to implement a digital asset dissemination architecture based upon web standards. The dissemination architecture will provide a mechanism to add useful "views" to a particular digital artifact (i.e. asset, schema, or metadata instance), and bind those views to consuming services.