Zotero is a powerful all-in-one tool for collecting, managing, and citing research sources. Beyond its almost magical citation–grabbing features, Zotero allows you to save, organize, and share references, and you can easily insert properly formatted citations and bibliographies directly into papers using Zotero’s add-ins for Microsoft Word or LibreOffice. It's an essential tool for anyone doing academic research and writing. You'll never do bibliographies the same way again!
MIT has a subscription to Zotero which provides MIT affiliates with unlimited storage. The unlimited storage will be automatically applied if you have a mit.edu email address affiliated with your account.
To add an email address, login to your Zotero account and add an email address under "Manage Email Addresses".
You can verify your storage amount under the Storage section of your account.