|Using community / Using external groups|
External groups provide an area where standard community users can work with people from outside the community, external contributors. Only secret or private groups can have external access.
You can use external groups to invite people from outside your community to collaborate with standard community users. For example, a user in a music label company's community could create a private group for a collaboration project they're working on. They could then enable external access to the group, invite the external artists who will be participating, and use the group to post schedules and communicate ideas. The external artists are limited to viewing and participating in this group only. They can't see anything else going on in the community.
Groups with external access are designated with visual cues such as either orange Externally Accessible text or the orange eye symbol that means people from outside your company are welcome in that group. You can find the following bright orange sign post at a group's home page.