Overall, I can't say I'll be participating in either activity though.
Also how is sending a link or notification about new pictures different from sending actual images. In case a group link is created.
It is unlikely that without notifications, people will actually go and browse the link for new pictures. In that case isn't it same as posting it on your Facebook profile as an album with appropriate privacy settings?
Exactly. I think the point is that FB's privacy settings are difficult for the average user to understand. FB also has a public-by-default policy, whereas The Fridge appears to be the opposite.
What about the situation where someone in a group goes 'rogue' and invites people who other group members don't want to see their stuff? These new members will see everything already posted... I think it's an important principle that anything you post to a group should only be visible to members of the groups _at that time_... otherwise you have no real control over the info you share.