Here's a long response I wrote in response to
Tom's brief sketch of a schema of music history and the relation between content and context. He gives us three eras:
The Pre-Recording Era
The Recording Era
The ???? Era (Now, Basically)
And I played with that:
Oddly, I think it works in the order you put it, but that the reasons are more cultural than technological. Which is to say that in what you're calling the "Recording Era," through the early '60s you don't get definitive versions of songs but multiple versions, this being true in blues, country, and show music, and I don't see where "resistance" is particularly the reason, but more 'cause that's how people do things (blues and jazz musicians always playing variations on each other's songs, varying the music and the words, and copyright not being particularly enforceable in those specialty markets). You'd have some signature songs, like Crosby for "White Christmas" and Chuck Berry for "Johnny B. Goode" but you'd also get multi-versions of "Night and Day" and "Blue Suede Shoes" and "Blue Moon." What recording especially does isn't to tie a song to a performer, but to deliver the performer's personality and idiosyncrasies across the airwaves and into the record grooves. You could say that this is what "freezes," that you're hearing SINATRA when Sinatra sings on record, though I'm not sure if "freeze" is the right word here for your point that the listener can't change that sound/that personality for herself. You might want to call this NOT the Recording Era but the Personality Era. Meanwhile, in the land of what you're calling context, there is a difference on the local level, with jukeboxes and DJs taking over from piano players and small orchestras. In the olden days restaurants might have a pianist or a musician or a small combo as a matter of course, and bands would play dances and dance clubs.
What you seem to be homing in on as the Recording Era I might just call the Rock/Singer-Songwriter Era, which is a later variation on the Personality Era, and I'll point out that I don't really know if there's an equivalent in Asia, for instance, or if it's primarily an Anglo-American thing. And even here you've got complexities in the story in that someone like Bob Dylan, Mr. Singer Songwriter himself, is doing cut-and-paste and alteration like any old blues guy, and he's not reverent towards even his own "texts," and as such he and James Brown among others are harbingers of the next era...
...which I'll call The DJ Era, except in a way everybody's a DJ (you're just your own home DJ), and even back in the DJ get-go of the Recording Era, DJs are often the ones in charge of providing content to the listener; we need to think of radio shows and dance nights as the DJ's original art form. The DJ takes over the live musicians' role of fitting content and context. But some of them are already fucking around with content early on: in Jamaica in the '50s they've gone over from just playing songs consecutively, with talk interspersed, to altering what they're playing, anticipating hip-hop techniques of extending instrumental breaks, playing one song atop another, inserting the talking into the songs rather than between them, and so on, though none of this gets onto record until the late '60s in Jamaica and then in the '70s in NY etc. as disco mixes and extended 12-inches, and in '79 on rap records (and in hip-hop there was the problem of how to adapt something that had been essentially live - albeit with prerecorded music as the "instruments" and source material - to record). A lot of what we call the present comes from that.
My point is that there's continuity across Eras from pre-recording to now, from Jolson-Durante-type performers and also from bluesmen through DJs to kids on YouTube, but there's also continuity from the Recording Era, in that YouTube vids/YouTube kids are conveying Personality across the wires every bit as much as the Rock and Pop Stars of the Personality Era. And one reason the Personality Era is holding on isn't just resistance and the attempt to defend copyright etc., it's that Personality is a powerful force, and the Taylors and the Rihannas and the GaGas and the Beyoncés are going to use that power, and I don't see anything in the Right Now era that would undermine it.
Two other things to take into consideration: reality TV like Jessica and Ashlee, personal life helping to expand the music and vice versa (though good old fashioned non "reality" TV shows are working fine for Miley and Demi and ilk), but also American Idol, which is a whole other ball or cylinder o' wax, in that it's built on covers like karaoke and a lot of YouTube, but it also is rewriting the past in a showbiz way that's very different from rock history. Neil Diamond and Andrew Lloyd Webber get their own nights, and Heart's "Alone" becomes a classic because Carrie Underwood switches hairstyles/genres and
flabbergasts and wows everybody with it (I thought she'd been just as strong
doing Tiffany, but that didn't produce the same shock).
A final thing: what did you think of the claim in
my extended freestyle mix of "Microwaving A Tragedy" that music's Internet story is words - written words, each somewhat popular song being accompanied by a swarm of words? To be idealistic about it, maybe what I've called the DJ Era, with all the remixes and alterations and YouTube covers and kids doing their own dance, along with a hornets' storm of written online argument and commentary, maybe all this should be called the Conversation Era.