It takes a lot of the hard work out of formatting references, leaving you more time for writing and less time stressing about commas.
Zotero's group functionality allows you to share a set of references with a groups of like-minded researchers. Once you have an account on Zotero.org the group functionality is available to you. Just set up a group and manage members by emailing those you want to join in. See Jason Puckett's page for more information.