In my knowledge cafes and workshops, a frequent question asked is "what is a conversation". Surprisingly, people cannot agree. Many think an exchange of emails, even SMS messages can be classed as conversations. I disagree.
Browsing the dictionary definitions on the web, conversation clearly involves talking. It is an oral, spoken activity, not a written one
Here is a definition from the Merrian-Webster dictionary:
"an oral exchange of sentiments, observations, opinions, or ideas"
And another from the Macmillan dictionary:
"an informal interchange of thoughts, information, etc., by spoken words; oral communication between persons; talk; colloquy"
The key words here are oral, exchange and informal.
So you can have a conversation, face to face, on the phone or via a video link.
Anything else such as email, a written letter, or an exchange of IM or SMS messages are not conversations.
I would also add that conversation is highly interactive and takes place in real time - so an exchange of voice messages is also not a conversation.
To my mind, the best conversations are face to face, you need to be able to sense other people in their totality; their dress, their body language, their habits, their perfume or cologne; you need to be able to reach out and touch them even.
This you cannot do over the phone or even a video link.
If you want a real human experience it must be literally face to face; body to body.
That's the way conversation evolved, long before writing technology, its what us human beings are good at
It's conversation as it exists in the wild.