Let's say I share something with a circle "family" and the circle contains some people that haven't signed up for Google+, so I just have their e-mail address.
When these not-yet-plussers sign up for Google+, will they then be able to see my posts from before they signed up? What about when I share a photo album to this "family" circle?
I assume that if a user eventually sign up to Google+ but uses a different address than what I have in my circle, then they can't see any of my posts (unless they're also public).
Best Answer
Although I didn't test it, I'm quite sure they do. If you add an e-mail address to your circles, that address would immediately be linked to that person's profile as soon as he signs up. Then just the same check happens when he tries to look at that post, he will thus be in your circles at that moment.
What I don't know is whether he will see your posts in his Stream if he logs in or whether he will only see posts made after the time he signs up.
I'd say, you probably got plenty of friends not on Google+ so plenty of possibilities to try it out, let us know!