If only Windows marketplace applications are supported on Windows RT, how do developers load their applications? If my friend writes something, can they load it onto my Surface?
closed as not a real question by ChrisF, Diogo, Journeyman Geek, Indrek, KronoS Oct 29 '12 at 14:00
It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, see the FAQ.
Developers can test their applications using a Developer License which they are able to obtain by using Visual Studio, it is free for them and allows them to run their application without it being published on the Windows Store.
You can read more about the Developer License.
If your friend writes an app and you want to test it on your surface, you will have to obtain a Developers License and also the source of the app from your friend so you can build it and run it on your Surface.
No, those sort of applications will not be supported on the Surface RT or Windows RT devices. Hence, if your friend writes something that you would want installed on your Surface, he/she would first have to post it to the Windows 8 Store, get it approved and published and only then can you download it to your device.