The name Mendeley is derived from a combination of Dmitiri Ivanovich Mendelyev, who developed the periodic table of elements, and Gregor Mendel, often called the "father of modern genetics".
The Mendeley blog has the full-story on how the name was chosen.
Mendeley is a free reference manager and academic social network. Users can manage and organize their references, create and share annotations, collaborate with other users, and discover new content in their areas of interest.
As documents are added to a library, Mendeley attempts to detect the bibliographic data (meta-data) of the document. Users can then add any information that is incomplete or missing. This information can be accessed both online and in the Mendeley Desktop, allowing users to view their library no matter were they are.
A large focus of Mendeley is its academic social networking. Users are encouraged to create a profile highlighting their own works and research interests, and to connect with others by following individual users as well as public groups. A user can build their online presence and use the information provided by others to network and collaborate.