Software that assists in communication among people.
EMail. Group Discussion software. Project Management Software. Shared Contact Management, Group Calendaring. General custom database development (vs MsExchange Public Folders). Instant Messaging. Knowledge Management.
Some would say that any groupware app has to be driven from an email client, since that's all anyone will use. Why might email be so more widely accepted? Is it just that it's the first thing people learn, or is there something truly fundamental to it? See Universal Inbox ideas.
For the moment, I will use the term Collaboration Ware to refer to an assembly of software and people/practices to assist a team (or network of teams) in accomplishing things.
Came across a new one from www.skippingdot.net: http://www.fetchserver.com/ --ZWiki:DeanGoodmanson