I often see questions that are on-topic here, but which may be of interest to stackizens on other sites. What is the correct way to cross-promote a question like this?
For example, this question about political islam is an excellent fit for our site. Since it's on topic here we can't migrate it anywhere else (nor do we want to!). However, the querant may get good quality answers from the fine people at Islam.SE.
Since the question shouldn't be migrated, how can I make users on Islam.SE aware of this question? Should I simply post something in their meta about it? Or is there some other tool?
The Islam question is only an example. There are other examples I've seen in political philosophy, economic policy or political economy, law, and other fields.