Mendeley Reference Manager is free software that you can use online and download to a computer. It is available for Windows, Mac, and Linux.
Note: An older Mendeley program, Mendeley Desktop, stopped being available for download in September 2022. For more details see the "Introducing Mendeley Reference Manager" blog post.
Best features: Free (up to 2GB of online storage); user-friendly interface; ability to work offline.
Drawbacks: Small number of reference types; limited group sharing for free accounts; no Google Docs integration (only MS word).
Mendeley Reference Manager offers automatic syncing between online and desktop versions.
Step 1: Create a Mendeley account at www.mendeley.com.
Step 3: Get Mendeley Cite from Microsoft AppSource.
Step 4: Add the Web importer to your browser for quickly adding articles or webpages to Mendeley.