Amazon has finally got its cloud licensing deals for its music locker service, with all four major labels, publishers and more than 150 indies aggregators signing up.

Amazon has now added scan-and-match features to its Cloud Player service to reduce users’ pain when uploading their music collections, while purchases from its Amazon MP3 Store are now automatically saved to Cloud Player.

Amazon has also split its Cloud Drive and Cloud Player features – the former is now for files and the latter for music, with separate subscriptions. Meanwhile, Amazon is working to bring Cloud Player to more devices, starting with Kindle Fire, with Sonos and Roku home entertainment devices to follow.

All good, but the real question here is whether these licensing deals and new features can move the needle for Amazon’s music ambitions. After all, Sony’s Music Unlimited has had scan-and-match for a long time, and has been notably quiet about its subscriber numbers – as has Apple with its iTunes Match.

Amazon’s press release has a full set of major-label digital execs hailing Cloud Player’s potential to help people discover AND buy more music, but we’ve yet to see strong evidence of cloud+store services doing this. And given Amazon’s record on sharing numbers on its digital services publicly, we’re unlikely to get that evidence from the company any time soon.