If I could just share a few comments of mine as a person who was very excited to get involved in his first Demogame (I had always seen/heard about them, but never got involved), but lost interest fairly quickly:
1. When I signed up, before the game started, there was a lot of activity and everyone seemed excited, creating groups all over the place. Well, it didn't take long before the group I had joined simply stopped doing anything. This is a common pitfall, I think, for anything. Everyone is excited at first, and things sort of die down as the game moves along. What you guys have been saying is definitely spot-on, there needs to be initiative in leaders of groups and such.
2. It was very hard for me to figure out what was going on with the game. I honestly could not tell where the game was, but it always seemed to be way ahead of where we were politically. Either that or it was hung up on waiting on someone to do something. There were tons of "official" threads, but it was kind of confusing and hard to find the information I was looking for. Not to mention things kept changing places (for instance, I remember the location of screenshots of the current empire changed a bunch of times) Things just seemed... all over the place.
3. This is partly due to me personally, but I felt like I really didn't have an effect on the game. It seemed to be a very daunting challenge to take an office, partly because of all the rules and stuff, partly because there seemed to be an "elite" group of people that always ran things (which is not necessarily all bad), and partly because it seemed like whoever had the actual game at the time was making almost every decision anyway (I could be wrong about this, but it was the impression I got).
I'm going to give this a shot again, and even try to organize my own group this time, so I'll definitely be here trying as well.