I've participated in several diceless online roleplays.
Been there, done that. I've called them "Freeform PBEM RPGs," with no rules, other than the notions of continuity that players themselves want to give them. Such games can be implemented right now, by anyone, without any technical constraints.
Getting enough of a population base to get started is the problem.
I don't agree. Once upon a time I GMed as large a number of players as I thought I could handle, to see what the sustainable limit of my output + player output was. I wanted to know what a text-based MUD could possibly look like, how far up my efforts could scale. At peak I believe I had 32 players. I had many plotlines, quite a number of which were definitely dying for lack of attention. To try to make the game survive, I consolidated them down to 4. Within 1.5 weeks I cancelled the game, it just wasn't tenable. I think that game ran 4..6 weeks, can't quite remember. I wrote full time, meaning 40+ hours / week.
What you actually need to make a sustainable game, is about 5..7 people. I believe strongly in "The Rule Of Three" : no more than 3 independent units of action going on at any time. It allows for creative diversity, but still keeps things perceptible and manageable for player and GM output.
Of course anyone is free to find out if, by sheer force of will and writing output, they can do better than I did. But I have my expectations and predictions of what will happen, so take those for what they are worth to you.