why not merge craigs list with my contacts book, and add in a publish and subscribe element. so that way i can subscribe to topics that i might be interested, and know who the people are - as my friends, or friends of friends. obviously this is the kind of thing that social networks could enable but i) none of them are comprehensive enough to include all the people in my contacts book ii) doesn't have good integration with contacts books and ii) doesn't have a publish-subscribe element apart from the status update, which is rather a blunt instrument.
we need a way of brokering interesting connections between people based on their collective set of interests that delivers a marketplace with enough liquidity (ie most people participate), but also keeps privacy and spam at bay. another thing for the boffins to work on.