http://www.pathofexile.com/forum/view-thread/546455Many people have asked for more information on how guilds work. On the social panel you can create a guild. Names are not unique, so call it what you want. Powerful guilds can obtain tags that appear next to their members' names in chat. This requires sacrificing a set of end-game Maps, each of which corresponds to a letter or symbol in the tag. Tags are unique and some symbols are much rarer than others. Tags can be 3-6 symbols in length. While you're in a guild, you can chat to other members (even across leagues!) with the & symbol. The guild leader can set membership permissions (Leader, Officer, Member). Officers can also invite new Members.
Guilds start with 30 member slots and you can purchase sets of 10 extra slots for 100 points ($1 each). There's currently a maximum of 200. We may increase this in the future once we fully understand their impact on server performance. Guild stash tabs (which are all nameable/colourable) can also be purchased. The guild leader can set permissions on which tiers of members can view, add items and remove items from tabs.
Only the guild leader can purchase microtransactions for their guild, but members and officers can donate points to their guild to help with these purchases. The guild leader can accept and reject point donations on the guild webpage (on this site). If they accept a point donation, then they are unable to kick that member out of the guild for three months. It's possible to reject donations if you don't really want to take their points.