Amazon also reduced pricing for the service yesterday, which may be good for future subscribers, but is really annoying for those who already had subscriptions and just renewed for more money. Anyone who spent several weeks uploading music files one year ago likely didn't want to let their subscription lapse and have to repeat the entire process. Amazon waited a couple of weeks until everyone up for renewal was billed for a new year, then, less than a month later, they fundamentally changed the service's functionality and lowered the pricing.
I completely understand that Amazon's terms and conditions for the service give them the right to do this, and I also expect that early adopters often pay more for goods and services as prices drop. However, it's clear that Amazon was being quite coy here. They also issued an iPhone cloud player app shortly before "unlimited music" subscribers had to decide whether to renew, incentivizing re-subscribing.
It's clear that the new service is great for Amazon, as it allows them to de-duplicate their data and significantly reduces their bandwidth costs. It also may be a good thing for many customers who can get sanitized versions of their music files. As my original post mentioned, however, some users of the service saw the appeal of uploading and unlimited number of their personal music files (e.g., with meticulously edited album artwork, tags, and the exact compression they wanted). Without notice, Amazon is essentially replacing all these files for paid subscribers with different files, which sets a really bad precedent not just for music, but for cloud storage services in general. While I'm sure some users prefer the new functionality, others don't and it would have been better to allow users to opt in/out.
The other big story here is that at least some of the labels seem to have offered Amazon similar terms to Apple, showing that Apple's agreement for Match is not exclusive. In Netflix v. Amazon (video streaming) and Apple v. Amazon (music stores/matching), Big Content seems reluctant to let any one player dominate.
Regarding the press release: yes, it's official, it's linked from Amazon's more recognizable Amazon.com domain; for whatever reason, they post their press releases on a different domain.