What kills a social network? A group of internet archeologists have picked over the digital bones of Friendster – the pioneering social networking site that drowned in Facebook's wake – and we now have a clearer picture of its epic collapse.

Friendster was once the hottest thing in social networking. Google wanted to buy it for $30 million back in 2003, but – burdened by technical glitches and a more nimble competitor in Facebook – it was pretty much dead in the U.S. by 2006. That said, it trudged along for a few more years, helped by a relatively strong following in southeast Asia. Then, around 2009, a site redesign crushed it.

It ended up being a kind of "controlled demolition," with weakly connected chains of friends quickly disintegrating, says David Garcia, a professor with the Swiss Federal Institute of Technology and one of the authors of a recent paper analyzing Friendster's demise.

Just before Friendster relaunched itself as a gaming site in 2011, the Internet Archive crawled the dead network, grabbing a snapshot. Garcia and his fellow researchers used that snapshot of that controlled demolition as the basis for their research, which they describe as both a work of internet archeology and an autopsy.

What they found was that by 2009, Friendster still had tens of millions of users, but the bonds linking the network weren't particularly strong. Many of the users weren't connected to a lot of other members, and the people they had befriended came with just a handful of their own connections. So they ended up being so loosely affiliated with the network, that the burden of dealing with a new user interface just wasn't worth it.

"First the users in the outer cores start to leave, lowering the benefits of inner cores, cascading through the network towards the core users, and thus unraveling," Garcia told us during an online chat.

You can see the hollowing out of Friendster in this diagram:

The researchers describe heart of successful networks in terms of what that they call K-cores. These are subset of users who not only have a lot of friends, but they have "resilience and social influence," Garcia says. As these K-cores disintegrated, the whole Friendster thing fell apart.

If there's a lesson to be learned from the data, it's that it takes more than a lot of users to build a viable social network. They need to have strong connections too. So Facebook should be looking at the types of connections it users have and encourage them to connect to other strongly connected users, Garcia says.

In other words, strong networks are made up of strongly-linked people, not of stragglers.

Here's the Onion, predicting this story from a few years back:

HT The Physics arXiv Blog