Should local authorities be on MySpace or Facebook?

Over on the BarCampUKGovWeb discussion list Ian Dunmore shared a question posted today on the Public Sector Forums:
"I've been asked by a couple of people in my council if they can use the
likes of Bebo and Facebook to add a group to, to encourage young people to engage with the council. Firstly, it's Libraries and secondly our youth
people who want to promote a youth portal that is being developed."
In my reading for the Youth Work and Social Networking research I'm currently involved in, and in trying to prepare a series of briefing papers on Social Networking Sites I've been struck by how complicated an issue this turns out to be.
The answer depends on (at the very least):

