Solving your startup's cold start problem... or not.

Ouch.. was writing a looonng post here when my computer crashed... Rrrr murphy's law...

So well, haha, was writing I was not impressed by the article but the topic interest me a lot. And I was trying to figure out how facebook did? because imagine you come on facebook and there is nobody you know... It should have happened a lot at the beginning... Did the idea itself of facebook kept the people in it? Some kind of: "this site could be great" Really?

I also imagined that all first facebook's users were its own sales force. After a party: "Hey do you have a facebook account?" On a piece of paper: "Here is my facebook number cute boy"

EDIT: and also since facebook is very group-oriented, a member of a "group" (family, sport team...) would invite its mates to go on facebook.

Do you have any other suggestion to solve what is called here "the cold start problem"?