"The distinctive thing about Zotero 2.0, now in its beta version, is that it will allow you to store your collection (i.e., digital document archive, plus notes, plus bibliographical data) on a server, rather than on your hard drive. This has at least two important consequences.
The first is that you can add to your Zotero files - or retrieve them - from any computer with web access....
The other major development is that Zotero 2.0 allows users to create groups that can share data. Members of a class or a research group are able to transfer files into a common pool."