Planning to send your document off to an adviser for comments? Word's "track changes" function does not play nicely with EndNote, so you will need to "unplug" EndNote first. Here's how.
If you've used EndNote to produce a Word document, you can pull a separate EndNote library from that document including only the citations you've used, then send this library to a colleague. (Be careful though -- don't cite from two libraries!)
EndNote Web, through its “Sync” function, provides a free internet location to back up your desktop library and can even be used as a quick way to send citations to a third library. “Sync” means that it matches up the contents of both libraries, so that items added to or deleted from one library will be added to or deleted from the other as well.
EndNote version 7.2 allows you to create a library then share the citations and PDF files from that library with up to 14 people. This process differs significantly from sharing groups of citations through EndNote Web and is also more user-friendly.
Zotero can function as both local library (housed in your desktop or as a Firefox application) but Zotero.org also offers an online location for backing up your library. This "cloud" version of Zotero also allows users to set up groups to share citations and collaborate.