Unfortunately, in my field of work I'm forced to use a PC in the office. By making Messages a standalone app, I won't be able to iMessage with my friends and colleagues on my computer and will still have to use my iPhone. It would have been awesome if Apple included iMessage as part of their iCloud web interface (even if they also created the standalone app for Macs). This would have allowed people using any computer in the world (even as a guest) to interact with their iMessage contacts. I thought this was the route Apple was going to take so I'm a little disappointed with the news this morning.