The different stages of friendship, as i see them - internet eddition

After my last post about the rl stages of friendship, some people asked how I'd categorize online friendships.
Well, that made me think.
The previously mentioned rl Version was mainly based off of actions and such, things that just wouldnt be logical to consider online.
Rhe main point about an online friendship is that it can be anybody. What matters is not age, looks, scocial level, location, or anything of the sort.
All that matters in an online friendship are the people involved and their personalities.
Thus, its far harder to clasify.
For a while, i wondered if i could make it about how much they know about each other; but that isnt very good. Knowledge doesnt mean closeness, and yet there are things that would only be shared between friends.
So, it had to be included - at least the willingness to share, as well as the willingness to hear of anothers burden - but it couldnt serve as a base, that just wouldnt do.
Time was directly excluded. As example, While you could grow close with exchanging no more than a couple words a day, that would be the exception, rather than the norm.
So, what then? Because if its the amount of interaction... interaction, while bringing closer, can be vastly different in 'efficency' depending on the content and context.
The only real thing left... would be emotions. And those are hard to quantifiy, hopefully even for those that know them well, lol

But, I'll try putting them into comparison to actions/thoughts as i see them.

The 0. Stage : meeting someone.
Everybody on the internet is a stranger. Somehow, somewhere, you interacted with somebody and had your first conversation with them.
The 1. Stage: friendly interaction.
the main hurdle to overcome between the zeroth and the first stage would be the second conversation.
And indeed, this second conversation is quite important. Its possible to grow closer over time even without real word-filled interaction, but usually a conversation is needed. Preferably close to the first; the impression would grow stale otherwise, and might not actually count as getting over that first hurdle.

The 2. Stage: from the second conversation on, there might ne a third or a fourth and so on. But this would still be considered the first stage; the hurdle from the first to the second would be the desire to interact. After all; wherever you found this person, you're likely to run into them again, so it has to be one step up.
On NU we have the funny little follow system, so you can follow somebody when you think you'd like to talk to them again.
That allows you to see in your news feed (which i found a couple weeks or so ago) what other things you might talk about with this person.

From here on, things get rather hard to clasify.
But I would say the third stage is when you regularly interact with this person; not necessarily about the same thing, maybe even a couple small tidbits about yourself thrown in there when it fits, or a couple curious questions here or there.
At this stage its likely to genuinely care about the other person; maybe worry when they dont show up any more suddenly or something.

The fourth stage... it would either be based on understanding, as in knowing what the other means even when it isnt put to words, or in sharing things you wouldnt share about yourself, maybe your past, usually. This would mostly be things you wouldnt write in a public forum but only per pm or so~

The fifth stage... I'm not sure and it'll take a while to find that, so I'm posting this as is. This might be edited in at a later date.
However, if this were to be compared to rl version, there would definitely be need for a sixth stage, as rhe stages here are not equal in terms of friendship level to their numerical counterpart in the rl scale.
A fitting comparison would be... the fifth (rl) to the sixth (online), the first (rl) to the second (online), i think.