Spoon is very similar to VMware Thinapp, which I started 10+ years ago. Both have a lot of similarities to Docker, but there are important areas that cannot be addressed without Microsoft's support (see recent announcement between Microsoft and Docker). There are also other similar solutions in the industry like Microsoft AppV and VMware recently acquired a product called "Cloud Volumes".

Similarities:
- You can package your application into a single file and then run that on a clean Windows OS without installing. Startup times will vary - mostly based on the app. Docker advertises millisecond startup times, Thinapp is probably in the 10s of milliseconds to startup - but if the app comes packaged with a lot of fonts these may need to be extracted from the package first (not a problem for server apps).
- There are command line tools you can use to build your package using something like a makefile.
- You can package runtimes and support applications into your packages (.net, SQL server, etc).
- In Thinapp & others most filesystem and registry writes by the application are redirect to a sandboxed location. The sandbox directory can be located on another storage mechanism, so the VM can be treated as stateless.

Differences:
- Docker provides full namespace isolation between apps, another app on the same system won't affect your app. In Thinapp and others, this isn't 100% the case - for example names of shared memory objects, window titles, and most of the filesystem/registry will share a namespace with other processes. Thinapp has the ability to apply namespace isolation in specific cases, but doesn't do it by default because this can cause comparability issues.
- Docker provides network isolation. Each app gets it's own private network stack this eliminates port collisions, etc. This is not the case for Thinapp, etc.
- OS comparability is not assured, you still need to test your app on various OS's to make sure it works compared to Docker. For example, if your app uses a new API from Windows 7 - it will not run on Windows XP. In some cases this isn't true, you can use Thinapp/spoon to package an app with some DLLs from earlier or later versions of windows so it will run on older/newer versions - but that is not the case for things that use core system DLLs like ntdll or kernel32. I'm curious how Microsoft will address this when they introduce containers.

If you are running your app inside of a clean VM on amazon, you don't care as much about isolation of namespaces, filesystem, and network - so these solutions might be viable.

Microsoft had an old research project that died that is very close to Docker: http://research.microsoft.com/pubs/141071/asplos2011-drawbri...

Some other comments state this is the same as VMs, it's not. Application virtualization is a bit closer to Wine - it emulates parts of the Windows loader to load applications and it places hooks in all the application's API calls to access the filesystem, register, services, etc. It hooks all API calls that might need to access something from the system so those calls can be redirected to access data inside the package.

Anyway - Spoon's announcement doesn't go into any detail on what is new relating to what they are providing, it seems a bit of marketing repositioning to capture some of Docker's popularity. But - it could be a good place for them to be if/when Microsoft completes it's work on isolated containers, if they can provide a solution in that space that competes with Docker (and "free") they might find a market.