Giving “invites” to Google+
Google+ doesn’t have a formal “invite” mechanism, but you can still give people the ability to create an account by using the following method.
1. Obtain the recipients email address
(NOTE: it MUST be a @gmail.com account. External email doos not work right now)
2. Enter any text into the "Share what's new..." block.
3. Stick their email address into the "Share with" block (getting rid of everything else that is there).
4. Hit the Share button.
They'll receive an email with link which will allow them to sign up.