When I get a new email I potentially hear the ding of Mail.app up to four times, depending on where I am in relation to my various devices.
We've been through a number of different visualizations of the future: from everything is mainframes, to everything on mainframes connecting over thin clients, to commodity clients networked together, then back to thin clients, and now I think we're moving towards a slight modification of the thin client idea.
The iPad threw me for a loop. My iMac at home — center of my computing setup — appears to be falling off the cliff of relevancy. At least judging from these first few days post-launch, if I'm at home and not coding, there's very little reason for me to get up and hop on the iMac if my iPad's nearby. Not only is it just easier to deal with, but it's the iPad's singular focus that makes it simpler and more enjoyable to use. I use a MacBook Pro as my "work" machine, but the significance of a pure "work" machine is dwindling with the addition of new devices.
The foundation for distributed computing has been built: all my code is on the cloud, my documents/contacts/iCal are effectively on the cloud, and my most-used apps all tend to interface or be built around the web anyway. In short, I can get access to my data from most places as long as I have an internet connection. That's really cool, and it's a luxury we didn't have a few short years ago.
Syncing data itself isn't necessarily the problem anymore. It's the where of syncing, the when of syncing. If I'm on my iMac, it'd be great to get all my notifications pushed to me there. If I'm on my MacBook in a cafe, instant messages should get sent directly to my MacBook and not be duplicated if I happen to be signed-in at home. Same if I'm on my iPad. If all else fails, shoot it to my iPhone. The idea is that everything just seamlessly works, that I don't have to worry to sign out of my iMac before I head out the door, that I don't need to scroll up on Tweetie in four separate devices just to catch up on my tweets, that I don't get the same IM in three separate places at once.
It's not just notifications, either. My iPad was able to sync with my iMac or the AppStore to get my existing iPhone apps, but they were all a blank slate. I had to re-enter all my Google Reader auth details again. Local preferences I saved in one app didn't transfer over to another device. Part of this can be solved by dumping more functionality onto the cloud, but it also means some deeper integration from Apple for developers to sync their data cross-platform, for Apple to know which device to send notifications to. There needs to be an idea of your physical presence in relation to your computing.
It's weird it's gotten to this point. It's a completely strange concept, when you think about it; everything I mentioned can be solved today, with existing technology and some smart developers. The data problem is already solved; it's the data awareness that isn't. But that we've made it this far is pretty astounding. I swap between multiple machines a day, with my email, documents, and communication following me as I do, with relative ease. All things considered, cloud computing has had relatively few widespread, cataclysmic data loss incidents. And the devices themselves are far more futuristic than what we could have imagined a decade or two ago. Sometimes the future's fucking awesome to live in.
But other than that, fix that other stuff.