In this short proposal I wonder if it'd be possible to add a bit more structure and privacy to an open social network.
An alternative to the above social networks is FOAF (Friend of a Friend). It's based on an open Web data format (RDF/XML), so just like one's home page it's decentralized and very extensible. However, as I discussed a few years ago with Dan Brickley, the privacy implications of its openness are all the more severe. While my profile and friends are in someway limited to the gated community of one the services above, in FOAF my information is available to the whole world.
... This introducer key sits in a secured portion of my friend's profile. The simplest approach is for my friend to include it directly within his secured profile such that if he's willing to release the information he considers non-public to someone, then he's also released a third of the information necessary to get my profile key and consequently my email address. In effect, if 3 out of 5 of my friends are willing to share their non-public information (e.g., email address) to someone, they can then also get my email address.
