Not that you will want to do this often, but I discovered today that the “Presence” control displayed with every Person on a SharePoint site can be actually completely customized. Usually it looks something like this:
According to the MSDN documentation for NameCtrl:
A developer can create a custom control for displaying presence information if it has the same ProgID (Name.NameCtrl.1), uses the same method or property names, and provides the same functionality that is described in this reference. Functions can be created that handle the event in which the online status of a specified person changes.
What this means is that if you don’t have Office 2007 installed (or another version of the name.dll) then you can implement your own ActiveX control (in .NET or VB6 or C++) and name the COM class “Name.NameCtrl“. Then automatically this control will be called by SharePoint and will display whatever you want.
This could be handy for example when your customers don’t use Outlook as an email client or Office Communicator as an instant office messenger.