adding in to second the investigations idea! since people tend to have questions near the top of the post anyway, having an area for characters to find things out ICly would be a great way to keep players invested and active even outside of the direct thread reactions/engagement. some of that would obviously come down to "if it's more fun, fill out the setting," but some of it would probably be a good way to divvy out bits of plot!

the plot share option is also fun. obviously you don't want to turn every thread into handwaving, but in a setting like this - where characters have valid reasons to want to investigate things and leave an impact of their own - it can be helpful to have a way to encourage that