Contacts listing grow as we send and receive emails in Gmail. It is important to keep contacts organized and tidy for easy navigation to required contact at specific time. We have already seen how to merge duplicate contacts one by one in Gmail contact manager. Now you can automate this task of finding and merging duplicate contacts.
Auto find & merge of duplicate contacts
1. Goto http://www.gmail.com & login into your account.
2. Click “Contacts” on the left side menu in the inbox.
3. Click “Find Duplicate” button, it will show you probable duplicate contacts.
Make sure you review final duplicate contact listing. If you think listed contacts are duplicate, you can easily merge them by clicking “Merge” button. Quick and easy, what say? [via GmailBlog]
This post is really great..Another alternative I discovered is the so called Scrubly duplicate remover. The nice thing about this service is that it gives you the option of viewing the contacts to be merged in advance and picking and choosing the info you want to merge so you have complete control over the merged data. It also keeps a backup of your contacts.
Scrubly also supports Outlook, Mac Address Book and Google Apps contacts.