It’s impossible to evaluate the MySpace Music announcement until more details emerge and the product itself launches. But this is clearly a keystone event in digital music, with lots of potential. This is in the same league with Amazon doing a DRM-free MP3 store in terms of Big Deal-hood, if not quite up to the original iPod or iTunes.

Pros

– MySpace has an existing huge audience who have shown they like to listen to and discover music there
– It has a good track record supporting a broad variety of artists
– Doing this as a joint venture means three of the big labels have skin in the game
– MySpace is farther along than any other social media player in working with advertisers. But that’s not saying much

Cons

– Audio advertising while someone’s listening is going to have to play a role in digital music. Yes, I mean “like radio.” That nut hasn’t been cracked yet
– Who knows how big the ad supported catalog will be, and whether it’s truly an on-demand experience? I guess we’ll see, but consumer expectations are likely to be very high
– Amazon’s got a great digital downloads store, and it’s a retailer, and it doesn’t seem to have juiced digital download sales yet. Still watching that one

I suspect we’re going to see aggressive co-sponsored, highly interactive media campaigns involving music, viral passalong, and personal expression. No kidding. Let’s see them, guys.

Related Jupiter reports:
Ad-Supported Services
Digital Music forecast