When looking at the list of ideas, display the number of people who have opened each post. For an example of this, check out posts in facebook groups.
It would be great if users can vote on comments. Like stackoverflow.com: Vote for answers to push them to the top of the list or just answer "Was this post helpful to you?" with yes/no.
Currently, participants are only credited for having a strong opinion on an idea. If you don't feel strongly enough for or against an idea to promote or demote it, then you get no credit and that position is not considered. Yet there is a real difference between an idea that ...