Q:

How can one migrate questions for StackOverflow? 

How are questions from SO imported on Magento SE ? 
I first thought it was only old questions when Magento SE was released but this one is from April 21st: https://magento.stackexchange.com/questions/112037/migration-from-magento-1-to-magento-2

A:

Normal users only see some predefined migration paths. 
For Magento. SE there is only one, to Meta. Magento. SE

For StackOverflow it looks like this:

To migrate posts to different sites, you have to flag them because only moderators can do that.