> The first time I emailed a stranger, I swear my cursor hovered over Send for a full five minutes.

I would estimate communication is 95% non verbal and 5% verbal. The problem with online interaction is you are limited to this 5% while interacting with an almost infinite number of social groups and people.

Learning how to adapt to online socialization is learning how to adapt to being blind. Only you aren't blind, you are choosing to wear a blindfold.