Everyone is literally urinating themselves over this tablet that Apple better come up with on Wednesday, if they know what's good for their stock price.[1. If you aren't aware of the shenanigans, A Bigger Piece of Glass is a good place to start.] I can't say I'm not intrigued by a computer with a totally different form factor. My just over three year old MacBook is on its second battery, second hard drive, acquiring obnoxious keyboard and mouse issues, and starting to creak when streaming HD video from YouTube and Vimeo's new HTML5 betas. Nonetheless, I have a thesis and a nigh-infinite number of papers in my future so I can't imagine a software keyboard being a particularly wise decision. I did get to thinking what this sort of form factor would be good for. I haven't been able to divine from the froth of rumors a prospective weight for device, but a 10 inch screen would be about the size of a 3-ring binder. As long as they don't make the thing out of lead....
OH MY GOD IT IS THE FUTURE. Now, this sort of functionality exists already in the FreeHand MusicPad. But this would be (allegedly) another hundred dollars for a real computer that does other stuff too. This small amount of cursory research explains why, despite playing with lot of musicians many of whom are early adopters of technology, I have never ever seen anything on these lines used. This price point is entirely too high for a dedicated device for most musicians. FreeHand's website only has pictures of it being used by Sammy Hagar and Sting, who between them own a tequila company and a castle.
It's not that musicians are afraid of unreliable technology, I've been in several performances that involved laptops. But thinking back on it if they were displaying anything it was timekeeping rather than any sort of notated music. It's the same sort of philosophy that informs typographical projects like Markdown, letting computers do things they are good at like computing. This Tablet or Canvas or iBook or whatever will likely alleviate any hardware issues with any "digital music stand". So it comes down to software that provide significant advantages over paper copies. The ability to have a piano-player folder of music with you at all times is obvious, but probably not significant enough. [2. Piano players and percussions, regrettably enough, would still have hardware issues. The most popular solution to page turns thus far is by means of a footpedal and their feet are already up to something] Here's a best-case scenario:
I'm performing the Webern opus 18 songs for guitar, clarinet, and soprano. Webern was a jerk and wrote the guitar part on a grand stuff and I'm a dumb guitarist. A couple strokes and it's notated in a clef I can easily read. The songs are short (it's Webern!) so I can have the part on one "page", but can switch to the whole score for rehearsal purposes when. In fact when things are hard to line up (it's Webern!), I can see any combinations of the parts on any measure on want on however many staves I want either fully notated or just rhythmically. With or without words too. I could mark a cue on their device and it would instantly beam to the other two. This is the sort of thing that would make a device like this worthwhile.
That's very much a pie-in-the-sky scene, but those are all software solutions. Standardizing it to the point where all three performers of the example have the same program is where the real world comes and bitches everything up. Open source would be fantastic (like the Lilypond project, maybe?) but not only does the extension of the iTunes store to the tablet not bode particularly well for that but no publishing house in their right mind would agree to it. One thing I would like to continue is for composers to make money for their intellectual property, as little as it may be at the moment. We'll just have to wait for Wednesday to see what the thing will actually be, and then we can start working on living in the future.