Social networks rely on invite mechanisms to generate a bunch of their traffic but social proof says that the likelyhood of a person participating in an activity scales non-linearly to the number of their peers doing it. One person inviting you may lead to a 3% chance of action but two people may lead to 15% and 3 people might be 30%. Would a group invite mechanism help social adoption? The way I’m envisioning it, there would be a pointman who’s really, really passionate about someone else getting onto the tool. But what they could do is send out an invite for other people to be part of the invite. So what the user would see in the end is:

“John, Paul & Mary all want you to join facebook”.

Of course, once you join, you would automatically become friends with all of them and thus, be well on your way to a compelling user experience.

Similarly, on that vein, filling out voluminous profiles is a major disincentive for someone to join something. Why not let other people collaboratively pre-fill out parts of your profile so all you have to do is essentially add in your password and you have a fully functioning social presence.