Simile

Semantic Interoperability of Metadata and Information in unLike Environments, SIMILE, is focused on developing robust, open source tools that empower users to access, manage, visualize and reuse digital assets.

Connotea

Connotea is a free online reference management service. It allows you to save links to all your favourite articles, references, websites and other online resources with one click. Connotea is also a social bookmarking tool, so you can view other people's collections to discover new, interesting content.

Mekentosj Papers

Sick of that big pile of paper on your desk? Forgot in which article you read about that interesting experiment? Papers will revolutionize the way you deal with scientific papers. Search for papers using PubMed, directly retrieve and archive PDFs, and read and study them all from within Papers, your personal library of Science.

Mendeley

Mendeley is free social software for managing and sharing research papers. It is also a Web 2.0 site for discovering research trends and connecting to like-minded academics.

Mendeley Desktop is more than a reference manager:

* Automatic extraction of metadata and cited references from PDFs to create your own personal library database
* Tag, full-text search, share, and annotate your research papers collaboratively
* Back up your research papers to Mendeley Web and access them online