Can there be more than one neighborhood per city?
Yes, we expect a neighborhood will consist of up to 400 households to be most effective. You want your neighborhood to be big enough to yield enough referrals, and small enough that you're likely to know the referrer personally (or by direct reputation).
How much time does it take to be a moderator?
The short answer is not much. Once you set up the original list of users from your neighborhood, you just have to handle the occasional request by someone wanting to join or someone leaving the neighborhood. We estimate about an hour to get set up, and then five minutes here and there throughout the month.
Is it safe for kids?
Yes, although we recommend that parents put in referrals for kids that don't include any identifying information, just to be safe. For example, if John and Suzy have a daughter who babysits, they should give John's contact information for the referral, rather than their daughter's.