If they are there. I have to wonder how many will play for a week or two and be gone forever. Or come in just troll and cause problems. Playing on a private region with only friends helps this but you need about six friends who all want to play this game and all have the time to dedicate to it.
I may try to get around this by making a private region and not inviting anyone to it, but I really only want to build one city, not a half dozen and I'm afraid this game kind of makes it necessary later on to trade and such with neighbors.
Gads. Why do I feel like I'm playing SimCity Facebook... --- I'm glad your opinion differs from mine. What a boring place this world would be if it didn't.