The functionality overlaps amongst Groups and Team sites (or Sites as they are called in Office 365). Here is a quick explanation of which one to use when and why.
Office 365 Groups
- Team site containing a document library, a shared calendar and a OneNote notebook
- Edit permission is automatically assigned to all members. External users can also be included.
- It also creates a Delivery Group recipient which contains all the members of the group
- Office Groups, once created are visible in Outlook, Outlook for Web, Groups apps, and OneDrive (on web)
- Outlook has a special toolbar for Groups.
- On web access, Insert Attachment dialog also offers to share links to Group specific files.
- Meetings added to the Shared Calendar automatically appear in the personal calendar of each member automatically.
Creating a group is an extremely simple task. Just specify a name and list of members. That’s it.
Now let us look at what team sites offer.
- Document library, and OneNote notebook is automatically created using the default team site template. Shared calendar needs to be created manually.
- Security rights need to be assigned manually.
- It does NOT create a Deliver Group in exchange.
- The sites are not exposed in any other application. You must know the site address to access it.
- Shared calendar needs to be manually connected to Outlook. Even after the connection, the personal calendar and shared calendar remains separate. Users must activate both calendars in Outlook and use the overlay mode to see the combined view.
Which one to use when?
That is why, Groups is a sort of simpler superset of Team site feature set. In addition, there is no need to talk to IT
Groups vs Team Sites – Which one to use when?
Groups are usually time bound and initiative specific whereas Team Sites have a much longer life-span.
If you have a long term team – which usually means a department or a unit within a department, Team Site is more suitable.
If you have a group of people which are cross-functional and are working on a time-bound project, Groups is a better option.
Students working on a specific project will benefit from using Groups. On the other hand, a Team site is more suited for all the students in a given class or division or batch.
More about Groups
Read the Office 365 Groups: Knowledge Pack for more details.