Excerpt from this article:
…somehow, meeting someone you know online platonically has become a far more awkward endeavor than a random OKCupid date. You know her but you dont know her. Do you shake hands? Do you hug? Do you do that open-palmed half-wave? God forbid she goes for the hug and you go for the handshake like you’re in some jerking, uncoordinated, chest-poking dance.