Wiggio - Service is discontinued and taken private (internal part of other service)
wiggio.com has long provided a free integrated community experience but the last few years has lagged behind other services. Wiggio was one of the first to offer many functions from one integrated platform. The feature set includes forum-based messaging that also doubles as an email list server, file repository, collaborative document editing, group calendar, private messaging, group polls, group meeting scheduling, group conference calls, and group video conferencing.
They use your email address as your username. Members can elect to have their email address hidden so they can retain some level of control over communications. Members can still direct message with each other through the service, however. You can also start a conversation with any subset of people you want. The messages are posted with a note at the end indicating the participants in the conversation.
Once you login you see a list of groups to which begon on the left sidebar. In the center is an area displaying your message "feed". The feed is where you are notified of any new messages in your groups, new files uploaded, etc. The center area of the page can be switched to view the file repository or the group calendar. A list of group members is provided on the right sidebar to make it easy to select specific people to send messages to.
If you are a member of more than one group that is using the service you can elect to see all your group messages displayed in your feed interspersed or select one group and filter the feed to just that group. Either way the messages are display in reverse chronological order.
There are controls to enter a reply to any given message in the feed and replies are organized in threads to help follow conversations.
Overall the service works well. It is full-featured for a free service.
The drawbacks come in member management. There is no provision for moderating a member so this service is only appropriate for groups that are small, friendly, or otherwise do not need to manage what anyone says to the group. Our groups ran into this when one or two people started ranting and there was no way for us to stop them short of kicking them out altogether (which was a politically unwise thing to do).
The service also adds some boilrplate to each message which gets annoying after a while. (It also force all messages to be HTML which is a security problem for some.)