Google Groups is a feature of Google Apps that makes it easy to communicate and collaborate with groups of people—such as project teams, departments, office locations, and special-interest groups. A group is like a mailing list: It contains the email addresses of its members, but also has its own address. Using just the one email address for the group, you can:
District Email Groups vs. Personal Contact Groups: You might be wondering how Google groups differ from the contact groups you can create in your My Contacts list in Google Contacts (click Contacts in Gmail). The primary difference is that a Google group has its own email address, so it can be shared in our Groups directory and others can send messages to it. Your contact groups, on the other hand, are for your personal use, to make it easy to add a list of addresses to your email messages and meeting invitations. They don't have their own email address, so no one else can send messages to them.
Google groups and shared corporate contacts: Google groups aren't included in the shared corporate contacts you access in Google Contacts. Instead, you'll find them all in our Groups directory. However, after you send a message to a group, it appears in your All Contacts list in Google Contacts. From there, you can easily add the group to your My Contacts list (although this isn't necessary).
Google groups and "auto-complete": After you send a message to a group, it's automatically added to your All Contacts list in Google Contacts. Now, whenever you want to send another message to the group, invite the group to a meeting, or share a document with the group, just start typing it's address and it will be completed automatically.
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