I have a question about my pcDuino, but do not know where to put it. Would it be on-topic at Raspberry Pi Stack Exchange, or any other place on SE? Or, would it not have a place on the SE network? This could also apply to BeagleBone, Banana Pi, or any other board that is like the Pi, but is not made by the Raspberry Pi Foundation.
The issue has been discussed here on Meta a few times before. Current consensus is that non-Pi boards are off-topic here.
That leaves you (unfortunately) with multiple options on the network depending on the nature of the question. There is no one-page-fits-all here...
- General programming questions: https://stackoverflow.com/
- Hardware/software and networking issues (unless it's programming or electronics): https://superuser.com/
- Linux/Unix questions: https://unix.stackexchange.com/
- Electronics and low-level hardware: https://electronics.stackexchange.com/
... but checking the sites' rules about what's on- or off-topic there is of course highly recommended.