STEVE INSKEEP, HOST:
Facebook is redesigning its front page. The news feed, which is what Facebook's roughly one billion users - however many of them enjoy it - see when they log on to the site, will be rolling out what's being described as a radical new look over the coming months. These changes are meant to increase user engagement on the site - to make it easier to navigate on smartphones and provide even more highly targeted advertising.
But as NPR's Steve Henn explains, big changes can be precarious moments in the life of a social network.
STEVE HENN, BYLINE: Remember Friendster, the first social network to achieve large scale success? Founded in 2002 - before Facebook or MySpace - Friendster turned down a $30 million buyout offer from Google, back when that kind of money still turned heads. At its peak, it had more than 100 million members, and then in 2009, it made some changes to its site and suddenly, Friendster collapsed.
DAVID GARCIA: There was a point in which it were really the most important social network.
HENN: David Garcia is a researcher at the Swiss Federal Institute of Technology in Zurich. He analyzed data from Friendster collected during its death throes and has come to some interesting conclusion about what can make an enormous online network vulnerable. In Friendsters case it began with a specific trigger.
GARCIA: There was a change in the user interface, plus there was the alternative of Facebook.
HENN: Friendster redesigned site was awkward to use - unfamiliar - and some dedicated users left. With each new defection the site became less useful to the people who remained behind.
GARCIA: If most of your friends have left the community, you will leave it too.
HENN: Every time a friend on your network leaves -a network become less valuable to you. Your calculus changes. Garcia's autopsy here, starts with a simple assumption - that when the costs associated with being on a social network begins to outweigh the benefits, you'll leave. And what's true for Friendster in 2009, Garcia says is probably true for Facebook today.
I met Ian Fisher in a coffee shop in Palo Alto - his three month old daughter balanced on his chest.
What would cause you to leave a social network, cancel your account, delete your photos and abandon it?
IAN FISHER: I actually did that. About two years ago, I canceled my Facebook account for about a year. And I did that because I was reading so many article about privacy concerns on Facebook, and I was spending so much of my time on there and realizing I was getting essentially nothing out of it that was good for me.
HENN: In 2010, a changes in Facebook's privacy policies led lots of people like Ian Fisher - to leave the network - but unlike Friendster, it didn't implode. Turns the vulnerability of social networks to the kind of mass defection hinges on how most people on the network. If most people use it to keep in touch with just one or two friends, when one of those friends leaves, you're more likely to leave too. But if you have a thousand connections, the network's more resilient. And in Ian Fisher's case, a few years after he left Facebook, he decided to come back.
FISHER: Because there were people that I didn't know how to get a hold of - but I, - there were my sort of peripheral acquaintances that I didn't get a chance to connect with quite as much. I'm still trying to decide whether it's worth it or not - I'm not totally convinced that it is.
HENN: It is for now - maybe just to share pictures of his new baby. But researchers say Facebook still needs to be cautious. When you're tweaking a social network - even one as big and successful as Facebook - you don't want to scare off too many people at one time, or you could create a cascading exodus that's difficult to stop. And that may be why Facebook is rolling out it latest update very, very slowly.
Steve Henn, NPR News, Silicon Valley.