A vital social space where genuine relationships flourish, or a forum for vapid, transient interaction?
Since they exploded on to the internet, debate has raged about the value of social networking sites such as Facebook and MySpace.
At the weekend they drew condemnation from a senior figure in the Catholic Church who said they fostered the idea that friendship was nothing more than "a commodity."
Social networking on the internet "dehumanises" community life, according to the Archbishop of Westminster, Vincent Nichols.
He added that it encouraged young people to put too much emphasis on the number of friends they have rather than on the quality of their relationships.
It is a debate which rages in one Edinburgh household, where Facebook-hating IT expert Alan O'Riordan, 32, lives with his girlfriend, Lindsay Gillan, 30, a Facebook fan.
Mr O'Riordan said: "I don't use Facebook because I don't see it as a good use of my time. I don't like the way you have to sign into it, and I don't want people knowing all my personal details. It seems everybody's on Facebook and there's a little bit of Big Brother going on.
"It can be a waste of time, and it can be a downer for a couple if one of them's on the computer the whole time, and the other's trying to get them to engage in something else.
"I don't think people phone each other as much, or write to each other any more. It's all quick instant messages, and typing online instead of face to face."
But Ms Gillan, a financial adviser who has 98 Facebook friends, said: "I feel like I'm keeping in touch with people more, because of Facebook.
"I've got two ex-colleagues who live abroad and if I wasn't on Facebook I'd probably have lost contact with them, not intentionally, it's just the way these things are.
"Using Facebook doesn't make me less able to form relationships. We're having a family picnic soon with my mum and aunts and uncles and cousins.
"Rather than having to phone them all individually, I just put up one notice on Facebook, and they all replied.
"It's not making us isolated, it's brilliant."
That is not a view that is shared by the Archbishop of Westminster.
He launched his attack on social networking in the wake of an inquest into the death of a 15-year-old Cheshire girl, Megan Gillan.
She took a fatal overdose of painkillers after being bullied by schoolmates on the Bebo website.
The Archbishop said: "Among young people, often a key factor in them committing suicide is the trauma of transient relationships. They throw themselves into a friendship or network of friendships, then it collapses and they're desolate.
"It's an all-or-nothing syndrome that you have to have in an attempt to shore up an identity, a collection of friends about whom you can talk and even boast.
"But friendship is not a commodity.
"Friendship is something that is hard work and enduring when it's right.
"I think there's a worry that an excessive use or an almost exclusive use of text and e-mails means that as a society we're losing some of the ability to build interpersonal communication that's necessary for living together and building a community.
"We're losing social skills, the human interaction skills, how to read a person's mood, to read their body language, how to be patient until the moment is right to make or press a point."