Helping them pass the time certainly, and perhaps helping them get laid.
You're dead right that each generation wants to be in a social space that feels "theirs", but I don't think that precludes using the same infrastructure.
When I was a teen, I drove on the same roads and used the same telco and USPS as my parents, even at my most rebellious times. In Facebook's case, each user "feels" a tiny piece of the overall universe, and one which is vastly disproportionately populated with people they've mutually selected. That, coupled with meeting jwz's use case above, makes me feel that Facebook is pretty well positioned to succeed.
Terrible comparison, I use the roads because there are no other, better alternatives. When given a choice I always pick UPS or FEDEX over the post office for shipping, and looking at the financial position of the USPS I am in the majority.
Those industries exist because of the government monopoly, a new better social network can arise in an instant.
You're dead right that each generation wants to be in a social space that feels "theirs", but I don't think that precludes using the same infrastructure.
When I was a teen, I drove on the same roads and used the same telco and USPS as my parents, even at my most rebellious times. In Facebook's case, each user "feels" a tiny piece of the overall universe, and one which is vastly disproportionately populated with people they've mutually selected. That, coupled with meeting jwz's use case above, makes me feel that Facebook is pretty well positioned to succeed.