This is really interesting – Amazon has released S3, which offers open web storage for $0.15 per gigabyte per month, accessible via web services (REST and SOAP interfaces provided) and BitTorrent. Authentication is via Amazon login, and you can use access control lists to control access to the files.
Interesting that there’s no WebDAV interface to S3, at least from my brief look at the documentation.
They’re guaranteeing 99.99% (“two nines”) reliability.
This could point the way towards ubiquitous cheap online storage accessible via Web interfaces.