Google Contacts back up and restore for 30 days included!

[riso]

With multiple devices syncing your contacts this way and that, with changes, additions, and deletions from all over the place, it's pretty easy to end up with a muddle mess of data. Thankfully, if you sync your contacts with Google, you've now got a backup plan should everything hit the fan. Google has introduced a restore feature for Google Contacts that allows you to undo any mistakes you've made up with up to 30 days backup. Working a bit like System Restore for Windows, Google takes snapshots of your contacts and restore them to back to the way they were 10 minutes ago, 1 hour ago, yesterday, 1 week ago, or any custom time up to 30 days ago.

So next time your iPhone decides to wipe your contacts, or Outlook takes issue with your friend's new address, you can just hop on over to your Google Contacts and hit restore. Brilliant.
source: Gmail Blog