Amazon isn't just the world's biggest retailer. It's one of the world's biggest cloud services providers, and its servers power some of the internet's favourite services.
In 2011 it decided to join the consumer cloud party too, and since then it's quietly added some very useful cloud-based features. The most recent example is Amazon's AutoRip, which automatically adds MP3 versions of CD or vinyl records you've bought to your cloud music player - and which checks through your purchase history to AutoRip CDs and records you've bought in the past.
AutoRip isn't perfect - it can only rip the records it has the digital rights for, so don't be entirely surprised if your prized 1977 punk rock B-sides collections aren't covered. But it's still a clever and appealing feature, enabling you to stream music you can't remember you bought or just listen to new purchases before the postman delivers the CD.
As CEO Jeff Bezos put it: "What would you say if you bought CDs, vinyl or even cassettes from a company 14 years ago, and then 14 years later that company licensed the rights from the record companies to give you the MP3 versions of those albums… and then to top it off, did that for you automatically and for free?"
The centrepiece of Amazon's consumer cloud services is Cloud Drive, which offers 5GB of free storage and comes with desktop (PC and Mac), iOS and Android apps. If 5GB is insufficient you can add additional storage, with plans available from 20GB (£6 per year) to 1,000GB (£320 per year).
You also get Cloud Player, Amazon's online music streamer, which you can access via the web or via iOS and Android apps. The free version is limited to 250 songs, with the option to have up to 250,000 songs for £21.99 per year.
In the US Amazon additionally offers Prime, a mixed bag of benefits that costs $79 per year and offers unlimited Kindle ebook lending as well as access to Amazon's Instant Video service. Non-US customers don't get the video option: while Amazon owns the streaming video and DVD service LoveFilm, it currently keeps it at arm's length. Amazon also has an App Store for Android - not just the customised Android that powers its Kindle Fire devices, but ordinary Android too.