No. If someone already has Direct messaging (for example, through their EMR) you can exchange with them. 

If they do not have Direct messaging already, you can invite them to use Kno2 via the invitation platform, Connect with Others, by clicking on the envelope in the upper right hand corner of your Kno2 screen near the Support Center. Enter their name and email address; they will receive an invitation and can sign up for the subscription level of their choice.