DIY Social Networks? Cool!

Yesterday I joined the IAB Forum in Rome, where I heard triumphant voices about the future of advertising on line, though in a rather old manner.
Today I came through this post at Social Media Insider, from Catharine P.Taylor,titled

Is It Time For DIY Social Networks?

Why I connect the two facts?

Because I agree on the fact that the future is in small but focused Social Networks, connecting people with attitude, while the Social hubs, as Facebook, MySpace and Bebo, will be crowded by marginal audiences.
And advertising is today running behind the Social hubs, trying to figure out a way to make money and it may catch them when the crucial targets will already be on the leave.