As you know you can hide your primary email address from non-friends but if by mistake you add a unknown person to your friend list, then he/she will be able to see your primary email address which you use to login. He can send dangerous emails (keyloggers etc.) and steal your Orkut account. There are two Methods to be safe:
1. Changing Primary Email:
Go To Edit Profle Page of your profile, then click on COntact tab and change your Primary Email address to some other id, which you don't use much. Your login id will remain same but your friends will see your other email id.
2. Using Fake EMail id:
It is the most effective way of hiding email id, but it requires a new account, If you have some larger communities and want safety, then follow this method:
Create a new Orkut account, On the Sign Up page enter any id which does not exist like firstname.lastname@example.org, email@example.com etc.
Then after entering other details, you will be redirected to your home page and with a message "Verify Your Email", Just igonore it and do as stated below
Now Go to google.com, you will see your fake id on the top-right corner firstname.lastname@example.org, You can see "My Account" Option there.
Go To "My Account Page" and create a gmail id from there. (You can see it under Try Some More)
Done! You have your new login id but your friends will still see your fake id :| Enjoy
The smile pockets a rattling controversy.