From my original post:
Assuming Apple will provide iMessage functionality on the Mac, I see four options:
- A new iMessage app in the App Store
- An update to the FaceTime app currently available in the App Store with iMessage integration
- An OS X Lion update that includes an updated version of iChat with iMessage integration
- A new app in the App Store that combines the functionality of iChat, iMessage, and FaceTime in one place
Their current solution partially matches #12, #3, and #4. I think the closest match is #3. They did basically just add iMessage support to iChat, but also renamed the app from iChat to Messages.
Interestingly, chat windows that are using iMessage have a button to initiate a FaceTime chat, but the button opens up the FaceTime app ready to make a call rather than having the FaceTime functionality built in. Perhaps that consolidation will come with a future version of Messages3.