It depends on how much time you have to manage/maintain it. With Google, you can add in response verification - e.g. a codeword. When somebody wants to participate it, they can be added to a group chat on TCLA, and then every couple of weeks, change/update the codeword (posting the new one to the group). Of course, it relies on trust - but it means if somebody posts false info, they can be removed from the group.
Alternatively, I can try think of a specific polling system that exists (or try to code a basic one and host it on AWS or something if I have time). Very simple, when a user requests it we add a firm to the list. Then people can submit for that firm whenever they receive progression / PFO, and it is tracked on a graph with dates etc. Different colours for PFO/progression. Again, some sort of password verification process, like with Google Forms.
^ Maybe something already exists like this for a xenforo add on, though? I haven't used XenForo since I last hosted a Minecraft server.
(I seem like such a nerd reading this back lol).