You can PM now.
No tagging works now in Q2A :) Actually I'm currently trying to do it in a similar way as FB and hopefully it will work at least with CKEditor. Also, the main job for me now is to ensure a proper Email framework which gives full freedom for users. i.e., Any individual can choose from his setting for each kind of event whether to receive 'Email', 'Notice' (from notification plugin), 'Push Notice' (only on Android app). The main use of this is not just for the usual Q2A events, but admins can also create new types of notifications. These two work will be opensource; though as of now I cannot guarantee that they will be proper plugins -- might be specific to CKeditor or even require other free plugins to work because my priority is to get them working asap. Then the Quiz plugin -- which is not free also needs extensions. So I'll be busy with these for quite sometime.