Social networks and you

Social networks touched my life several times today, unrelatedly - A news article about teenagers forsaking Myspace for Lent; a series of responses to a request for advice on orkut; a new widget on this blog (see the sidebar) that lets readers add scraps on my orkut; and a daily horoscope that advised me to reflect on past relationships and what I've learned.
It suddenly hit me that the people I ask for advice, for example - or any time when I need to get in touch with people that I'm not interacting with daily - I turn to my online networks first of all. Which means people who are not on them - or are infrequently on them - are virtually non-existent in my life.
It's... insidious. Because there are so many people there anyway, immediate purposes get served... until one day you realize that there were once people who played a very important role in your life, years ago, that for no discernible reason you fell completely out of touch with.
It's a new caste system, the haves... and the have-nots.