Board Thread:The Quarters - Q & A/@comment-24851786-20140424042002/@comment-24150802-20140424092044

It's a unique ID that distinguishes your guild from every other guild/party/group in HabitRPG. Normally, you don't need to pay attention to the Group ID.

If you want someone to join your guild, you'd send them the guild's URL (which has the group ID in it, but you don't need to think about that - just copy the URL from your browser's address bar and send the whole thing).

If you experienced problems with your guild, then you'd open a bug report in GitHub, and you'd need to include your guild's ID in that so the developers would know which guild to look at.