Improving communications is definitely key, but to add a bit more nuance to this conversation it is important to remember that another crucial element to increasing participation is to enable anonymous voting and an anonymous forum. Right now the state of affairs at PoH is one of an open panopticon, and the possibility that people feel intimidated to voice their preferences and opinions should not be ignored. It is unfortunate that the proposal for zk membership proofs did not take off, this should be high on the priority list if we want to make this DAO a healthy democracy.
While these solutions are not in place, extremely low participation could totally mean that a decision has no legitimacy and in such cases I think its reasonable for the person who created the proposal (looking at you @Mads) to take some steps to ensure that this is not the case, such as re-doing the vote and trying to engage the community more actively.
Another important reminder is that given we have a sybil resistant registry, an anonymous forum would not lead to a 4channelization process because it is possible to impose sanctions on those who break a certain Code of Conduct.