The reason why I am proposing this is that I saw this question which is about an android app that the user falsely expected to find in the Ubuntu-touch repository.
My reaction would have been to close as off-topic because it is not about Ubuntu, but android. However, it was not possible because the reason only mentions desktop OS. This is probably not the best example, but you can see the point:
We have users that talk about other desktop/server-OS than Ubuntu (Windows, OSX), and we will also have an increasing amount of users talking about other mobile-OS like android, WindowsPhone or iOS, I assume. For them, there are the sites WindowsPhone and Android Enthusiasts (and AskDifferent for iOS) respectively.
So in my opinion, we should expand the close reason "off topic because not about Ubuntu" to not only cover the several non-Ubuntu desktop OS, but also the non-Ubuntu mobile OS.
What do you think? Upvote if you agree, downvote if you disagree. If you want to add something, please comment or answer.