#I have a completely different suggestion.

What about rewording the banner to something like

> This is not about Ubuntu.  

> Please visit our [off-topic compass] to find out on which partner site in the Stack Exchange network your problem might fit best.

And then create a nice community-wiki site here on *meta.askubuntu.com* which looks like this:

> ##Q: My question was marked as off-topic, where should I ask it instead?

> You posted a question here and excitedly waited for an answer, but received a close banner like this?

> ![example image](https://i.sstatic.net/8tcoK.png)

> Read through the answers below to find out where your question would fit best!

---
> ##A: Unix & Linux

> Every question about any UNIX or Linux based system is allowed here.  
> However, if you use for example Ubuntu, ElementaryOS, OSX or Android, there are specialized sites for them, where you can get more specific answers.

---
> ##A: Stack Overflow

> All general programming questions should be asked here.  
> If you have working code and just look for optimizations, you're better of at Code Review though.

---
> ##A: Super User

> This is the most general site all about computers and related stuff. Every operating system is welcome, and so are hardware problems.

---
... and so on, one answer for each possibly related site.