One of the major problems review services have with getting of the ground is building a critical mass of reviews before it becomes a self sustaining community. Yelp has done it by focusing on a few metros and copious amounts of parties. VibeAgent, with their older crowd, plans on rewarding top users through “travel-related” rewards.
Isn't critical mass of any community always the problem of all communities?
How do you crack the niches? How do you crack the small towns?
Don't rewards have the potential to bias the system?