How can a non-Deskmate account holder follow any content that I need to share?
A user does not need a Deskmate account to access content you share publicly. That content is visible to anyone with a link.
A user does need to sign up for a Deskmate account if you share content specifically with them (for example as part of a group or to their email address). This is so that they can authenticate and your content is only shared with those you wanted to see it.
That level account is free to sign up to for the viewer.