With contact groups you can easily organize your contacts, making it easier to email a specific set of people. For example, if you created a contact group called "Soccer club", you could just send a message to that group, rather than sending out an email to 50 different people. Never leave somebody off an email again!

To create a contact group:

1. Click Gmail at the top-left corner of your Gmail page, then choose Contacts.
2. Select contacts that you want to add to a group, click the Groups button. , then Create new.
3. Enter the name of the group.
4. Click OK.

To add contacts to a contact group:

1. Select the contacts in the Contacts list.
2. Click the Groups button. 
3. Select the group you'd like to add the contact to, or select Create new to create a new group.
4. If you have multiple addresses saved for a contact, you can choose which address should belong to the contact group by opening the contact and clicking the small arrow next to the group you'd like to modify.