At first sight, Google Contacts seems to live a strange existence. Being separated into its own service instead of integrated into Gmail or Calendar, it feels minimalistic when compared to its convoluted competitors. Are you up for a bit of history and a dive into what makes contacts work very differently from other platforms?
Google Contacts was launched in 2009, back when nobody complained how horrible everything looked and it was cool to call everything beta. It was not spun out of Gmail - it was introduced as a service to connect all other services such as Gmail, Groups and Picasa (before it became Google Photos). Contacts was launched both for consumers and businesses at the same time.
When you open contacts.google.com, you will notice the list is not empty, unless this is your first day at work. In which case your HR has done an amazing onboarding job with you. Why is the list not empty?
It isn't empty because Gmail adds people you message (which includes replies) to your contact list. Before you jump to change this setting, let me explain why this preserves your sanity:
Google Contacts has three buckets of contacts:
The directory, which you can only read. Your company typically populates it with data from your HR systems (like Workday). It contains basic information (email address, phone numbers).
Other Contacts, which get created automatically (and should really be called "auto-contacts" or something like that). This is where Gmail puts the contact records it creates. You cannot directly edit them - well, you can, but if if you do, they become ...
Contacts (which should be called "My Contacts"). Think of Contacts as what people used to do: curated address books. Rolodexes we used to obsess over. Google will never add, delete or update anything you put here, this is your space. This explains the weird divide between Contacts and Other Contacts: Other Contacts is maintained by Google, Contacts is maintained by you.
Why should you NOT change this setting? Because this is how autocomplete works. External addresses get autocompleted from Contacts + Other Contacts. If it's not saved in there, you will have to type addresses like its 1999, and mistyping in the world of email can lead to email leaks and to calls with Corporate Security. Google is not only making it easy, but protecting you. You're welcome.
Duplicates do normally not occur. What can occur is this:
Some people have multiple accounts. Those are technically not duplicates. Contacts has a handy merging feature for that.
Beware of mixing domains, especially private and professional. If you deal with holger.matthies@mydomain.com, it is up to you to be vigilant which email you use. Perhaps go to contacts.google.com and delete this address so it does not get autocompleted.
Contacts definitely packs more surprises under the hull than it lets on at first sight. This was a full-on introduction for you power users - perhaps you got inspired to take a look at what has accumulated in "Other Contacts" and to groom your "Contacts list". Remember you can export that list and take it with you. And now that you are equipped with the basics - how about getting more value out of your contacts? Thank you for reading!