My wife recently got our first iMac. Since she already had people who shared Windows Messenger with her, she installed it only to discover that it doesn't have the capability that the Windows version has (for instance, it won't use her camera). Are the various chat products all mutually exclusive? If someone is using one product, can they contact and share games etc with people using other products? Can she switch to one of the other chat programs and regain her old Messenger functionality with her contacts (or more)?