> How do I message another user here?

- Just add a comment to that question mentioning `@Thijser` in the comment.
The user will get notified.

> I need 50 reputation to make a comment there. I only have 1

- In that case you can add an answer to that question (Which is suppose to be deleted saying that 'This must be an comment not an answer'). But the user will get notified.