Guilds and Interactions with Other Players

• How do I join a guild?
• How many times per day can I plunder another player's city?
• How do I obtain prestige for my guild?
• Can I change my neighborhood? I'm being constantly plundered.
• How do I visit cities of other players?
• How can I protect myself from being plundered?
• I was plundered despite having a city shield! How is this possible?
• The Guild Founder has become inactive. What can we do now?
• How does the friend list work? What are the limits?