Grassroots JoeThey weren't all that size of course, but we had 3300 of them and some definitely were on March 28th, 8 million, maybe a bit more all told.
And there will be still more next time.
Oh, and Indivisible did a 3k person poll of which 7% self reported having participated in #NoKings3.
Now that's a lot more than actually did participate, but the key thing is that approaching 24M people want to be seen as having participated.
That is serious progress.