It's not possible to truly implement Spotify as there is no P2P in HTML5 yet - but see Chromium's efforts with WebRTC.
It's also not possible to implement Dropbox. When last I checked, IDB in Firefox is at least an order of magnitude slower than a KV implementation with direct posix access. Most importantly, there's no proper native crypto api, and no way to let a user open a file from within a web application, and have it open in a native application, polling the file for changes to sync the different chunks when the user hits CMD+S.
It's also not possible to implement Dropbox. When last I checked, IDB in Firefox is at least an order of magnitude slower than a KV implementation with direct posix access. Most importantly, there's no proper native crypto api, and no way to let a user open a file from within a web application, and have it open in a native application, polling the file for changes to sync the different chunks when the user hits CMD+S.
Would be great if Public Web Apps could push these two use-cases through and do so without undue delay. Here's a related thread started by Tim Berners-Lee: http://lists.w3.org/Archives/Public/public-webapps/2012JanMa...