Fantastic question. The simple answer is that most people who are involved in community governance skew older, and older people primarily use Facebook as their social media fix, so getting updates about the goings-on in their communities or taking part in discussions about them is a natural fit between FarmVille updates and photos of grandkids.
Reddit works sort of all right for small and medium sized cities, but for most of small town rural America, people just use Facebook, not reddit, so it would likely be extremely hard to move people en masse out of Facebook for community organization. The network effects are simply far too massive to overcome no matter how good the other social network could be made.
Chicken and egg problem for people who work with chickens and eggs.
Reddit works sort of all right for small and medium sized cities, but for most of small town rural America, people just use Facebook, not reddit, so it would likely be extremely hard to move people en masse out of Facebook for community organization. The network effects are simply far too massive to overcome no matter how good the other social network could be made.
Chicken and egg problem for people who work with chickens and eggs.