After reaching a deal with the music industry for extended rights, Apple has added streaming functionality to its proposed iTunes Match service, further differentiating their services from Amazon's and Google's. What Amazon and Google offer is essentially a digital music storage platform, albeit one that exists in the cloud and is accessible everywhere. Their services stored the digital music you bought through their online store, and allowed users to also upload legally acquired digital music from other sources. When Apple first announced their iTunes cloud service, iTunes in the Cloud, it did the basic storage idea one better - instead of storing your music, the service would store a list of the songs you bought from iTunes, and allow you to download from the iTunes archive a high-resolution and DRM-free version of that song or album, regardless of whether or not your original purchase was in that format. The free iTunes in the Cloud service would also automatically access and synchronize iTunes music files across all of a user's Apple iOS web-connected devices. At the time, they also announced iTunes Match, which would allow you to list music files downloaded from other sources (up to 25,000 songs), which they would match with the newer high-res versions in the iTunes archive, and permit you to access those versions for download.
With licensing now in place, Apple's announced an additional major service addition - instead of just allowing downloads for later replay, iTunes Match will now allow users to "stream" songs from their digital Cloud library, again to a registered user's Apple iOS web-connected devices. (One report indicates this is not true streaming, but as it uses a cache on the device - still it offers instant replay rather than download and play.) The current beta being tested also allows "streaming" of TV shows bought through iTunes, but this has yet to be formally acknowledged as a feature of the consumer service. In this more recent announcement, Apple gave the price of the service as $24.95 a year.
With this move, the new iTunes Match service gives Apple a significant competitive advantage over Amazon and Google in functionality. The announced price for iTunes Match also significantly undercuts music streamer Spotify.us subscriber rates ($4.99/mo for low res feeds to computers, $9.99/mo for higher res feeds to computers and mobile devices). If the new service (now being tested in beta) works well and reliably after its introduction this fall, look for Apple's competitors to scramble to match features and prices.
Update - As I was putting this up, it's been reported that the streaming feature has been dropped from the most recent beta version of the software (iOS 5 beta 7). So maybe, maybe not.
Sources -Apple's iCloud to bring iTunes streaming music service, FierceMobileContent
Apple to Add Music and TV Streaming to iCloud, StreamingMedia.com
(edit - added Source and some new details on service)
(Update - see above. Source - Streaming disappears from iTunes Match Beta, Music Ally