Mendeley is a free, cross platform software that organizes and manages your documents both on the desktop and online. Mendeley was originally designed for managing and sharing research papers and collaborating online. But the versatility of this program allows even the average user to use it to manage and share office documents, ebooks and such.
Mendeley offers 500 MB of online storage to store or back up your documents online which facilitates remote access, syncing across multiple computers and collaborating with others. You can use Mendeley with or without the online storage. Without the online component, Mendeley serves as a local document organizer.
What Mendeley can do
Create a bibliography of your database: Mendeley can extract details such as keywords and cited references from documents and build an index out of it. This lets you search through your bibliography and filter by author, journal, keywords and even by assigning your own tags. Mendeley will even suggest papers not in your library which are similar in content or context.
Smart file renaming: Mendeley can rename your documents to more user-friendly file names like "Author - Title.pdf", making it easier to manage your docuemnts. There is also the folder monitoring tool, which allows Mendeley Desktop to automatically import any new files that you place into your selected folders.
Annotate PDFs: Mendeley has a built in PDF reader that lets you read full-screen, and the search-as-you-type function allows you to discover all instances of your search term immediately. You can highlight text with the text marker tool and add annotation to PDF files.
Generate Bibliographies in Word and OpenOffice: Mendeley has plug-ins for Word and OpenOffice that lets you automatically generate reference lists in over 100 citation styles.
Automatically important documents from the Internet: Mendeley features a bookmarklet for the browser using which you can automatically import document details, citations and any PDF files you find online into Menedeley. All of this information is stored directly to your Mendeley library.
Mendeley is available for Windows, Mac, and Linux.