There are three parts to make an run a app....
1. The SDK
2. The Binary Runtime
3. The AES Hash Key
You code your application with the SDK.
The runtime you have to configure and build on skypes servers, it will only work with the options
and platform you choose there and it only works with the generated hash key.
So basically Windows, Linux, Mac, Arm, Mips all have to have a different binary runtime, each
app is also suppose to only use the runtime that you register'd for it.
Your hash key is only good for 60 days and each app needs that in it's directory to work.
The binary runtime isn't a full-fledged skype client it's more of a command-line version and
yes it has to run in the background.
I thought that them making you pay for the sdk and then telling you that your not allowed
to make certain types of apps was kinda stupid.