Families are the same things as clans. They are a close knit group of individuals who share a common last name. Although you don't have to have your last name showing, most people will to show who they belong to. From what has been stated, you will be given access to special content such as a hierarchy system, custom clothing to show your families colors, a shared last name as stated before, a personal log-in family message, and a family chat channel!
Guilds
When two or more families, or clans form together they can create a guild. When you create a guild, you gain access to more special content such as guild-wide login messages as the family one, and guild chat. You also gain a guild insignia, special guild-wide abilities granted to the members, and bonuses for grouping with your guild mates on quests! However, lets say you want to play solo, and just be a lone-wolf in a guild, you don't need to be in a family to join a guild.
Great Houses
Great Houses are similar to that of alliances in previous games. They are composed of multiple guilds who share the same goal, and each of the houses will be representing a major faction in the world. When you form a Great House you will then be given the privilege to join the top of the power chain, and help control the balance of power in the world by favoring one faction, or another.
Great news though for people who still want to be recognized as a great family. You will never lose your identity in the lower tiers of power. A family will never cease to exist as an organization just because it joined an upper tier of power. However, mergers may happen causing political situations bringing depth, and a sense of actually being part of a new world to life
