The coordination website even kind of already exists—there’s a list of coordination tools/projects found here. None of them do what we need, though.

To me this sentence reads like you haven't put in the work to analyse why those tools don't do what's needed and why you think a new tool would do what's needed. 

I began writing this before r/WallStreetBets happened. Think about how wonderfully this second idea would work for coordinating them, though!) 

This again reads like not having seriously thought about the issue. Stock market manipulation is illegal. It's a lot easier to argue that you aren't really doing illegal coordination in the case of r/WallStreetBets where you have moderators that delete posts that look to much like illegal coordination then your system that wants to make it more explicit. 

The idea of creating a website for possible illegal activity to attack billion dollar entities and expect to have access to credit card processing seems strange to me. 

suppose you want to demand reform the FDA, but the lizards in office won’t do anything unless a critical mass of people demand it.

I think that's a very poor theory of change. Real world change needs a lot of negotiating between stakeholders and finding reforms that actually acceptable to a variety of stakeholders and not just a certain amount of people who ask for reforms at a single moment in time.

Happy to see enthusiasm and initiative here. I tried starting a few web startups in college and after; almost none worked, but the experience was useful.

I think you're massively underestimating the challenge of this. There were many products like Kickstarter before Kickstarter. To be successful you often need a combination of technical talent, marketing, and luck. This isn't to say that it's not worth a more intense endeavor; just that I wouldn't be as optimistic as your post sounds.

You sound quite similar to other young entrepreneurs I have known. Some wind up being successful, sometimes in part because of their overconfidence. Entrepreneurial claims often work better in other markets than rationalism / EA; when posting in places like this especially I suggest keeping things a bit more humble. 

So overall I think this is quite a bit more challenging than I think you think it is, but I don't want to discourage you from trying (though I really hope the process doesn't involve you burning over-hyped colleagues). I imagine more people making attempts at these things could be quite good overall.

I don't think postponing the payment does any good. If a person can't afford to put in the money rigth now they might fail to input when it is needed. Failing to put in the money when called upon would be really bad for the reliability of it.

In a case where failers are charged the process of verifying and ruling whether a thing was followed throught should be pretty robust. There might be user group and behaviour of "eggers" which do all kinds of actions to make others do things but don't actually themselfs do anything, such as hoping a protest happens without actually going themselfs. This could also seens as a possibly legit stance, ie if above board could be a constructive force.

Selling people that and action is a good idea is one part of it. However I see the core of it as people following one signal, that somebody gets to make a somewhat arbitrary choice which everybody else locksteps on. This would be like on what week or day the action happens. There the main thing would be to share contact info that the signal reaches when it is given.

In case you haven't seen, similar projects exist:

collAction

See also previous discussion here [LW · GW]

Related: Kickstarter for coordinated action sequence [? · GW]