This dissertation studied the design of five state education Twitter chats by interviewing their organizers. It categorized the chats by structure, from moderator-driven to host-driven. The interviews explored how chat design aligned with the organizers' teaching philosophies and the processes, tools and changes they used. The study found leadership, design, regularity and support are needed for online learning communities to develop. It concluded that without leadership, communities may fail, moderators are the social glue, and maintaining a chat is time-intensive and requires team support.