Requiring phone numbers could be effective. Though no matter what technology you use there will be a way to get around it. I think a good case study of a commu

Requiring phone numbers could be effective. Though no matter what technology you use there will be a way to get around it. I think a good case study of a community promoting non-anonymous comments is facebook. They use very little in the way of technology to prevent flamewars and spam, mostly it is user culture.