Thanks Björn for asking this question.
Private messaging definitely sounds interesting. We have this in our roadmap. Also I was chatting with @lisol about implementing this feature slightly differently. May be one can start a discussion privately and invite other developers to participate in it. In this case we need to be careful because people may start abusing this functionality. As you said, there are a lot of interesting people here - I think it'll be great if developers can connect with each other and chat/discuss stuff privately. So, yes - private messaging definitely makes a lot of sense and we'll have this very soon.
Also right now we are expanding the team and working hard to release the next version - which is a complete rewrite and has a lot more to offer. Our goal is to help developers share and consume knowledge in a better way and the next version of Devmag aligns pretty well with this mission. We are looking to launch a new and better Devmag towards the end of the month. I'll start a new discussion in the next few days and explain what we are up to, what this means for you and how you can help us build a better community for developers.
If you have any questions please ask here or email me at : sandeep@devmag.io.