Is it time for Craigslist to improve? 
brk: Craigslist is a good indicator of the world at large in regards to fraud and such.You could make it "better", but you would find the overhead required to make it better would also require a lot more resources to operate properly.So, you'd have to charge for more things, which would likely lead to decreased usage and accessibility to society at large, which ends up with the exact inverse of what you were trying to do.