Loomio is an open source software project developed by a worker-owned cooperative in New Zealand. It aims to enable groups to practice inclusive decision-making. Loomio was crowd-funded in 2013. It was launched the following year. According to Wikipedia, it continues to fund itself "through contracts with government and business, and also solicits donations from its users."
Since, like Wordpress or GitLab, Loomio is open source software, groups may  it on their own server or use the hosted version.
At the time of the writing, the Project Using Loomio section of the Loomio Wikipedia page, it out of date. Diaspora, for instance, used Loomio for a period. In this thread on their Loomio group, they describe why they have moved discussion to an instance of Discourse. It is quite possible that Marginálie will make a similar move. Threading is certainly an issue with the current version of Loomio. That there are numerous open source solutions to decision-making software, however, must surely be considered a good thing to any community endeavour such as Marginálie.