More than 900 million people worldwide check their Facebook accounts at least once a month, but millions more are Facebook holdouts.
They say they don't want Facebook. They insist they don't need Facebook. They say they're living life just fine without the long-forgotten acquaintances that the world's largest social network sometimes resurrects.
They are the resisters.
"I'm absolutely in touch with everyone in my life that I want to be in touch with," says Ma Li Arwood. "I don't need to share triviality with someone that I might have known for six months 12 years ago."
Even without people like Arwood, Facebook is one of the biggest business success stories in history.
The site had one million users by the end of 2004, the year Mark Zuckerberg started it in his Harvard dorm room. Two years later, it had 12 million. Facebook had 500 million by summer 2010 and 901 million as of March 31, according to the company.
That staggering rise in popularity is one reason why Facebook Inc's initial public offering is one of the most hotly anticipated in years.
Facebook still has plenty of room to grow, particularly in developing countries where people are only starting to get Internet access.
As it is, about 80 per cent of its users are outside the US and Canada.
Two out of every five American adults have not joined Facebook, according to a recent Associated Press-CNBC poll. Among those who are not on Facebook, a third cited a lack of interest or need.
Len Kleinrock, 77, says Facebook is fine for his grandchildren, but it's not for him.
He says his resistance is generational, but discomfort with technology isn't a factor.
After all, Kleinrock is arguably the world's first Internet user. The University of California, Los Angeles professor was part of the team that invented the Internet.
His lab was where researchers gathered in 1969 to send test data between two bulky computers - the beginnings of the Arpanet network, which morphed into the Internet we know today.
"I'm having a 'been-there, done-that' feeling," Kleinrock says. "There's not a need on my part for reaching out and finding new social groups to interact with. I have trouble keeping up with those I'm involved with now."
Women who choose to skip Facebook are more likely than men to cite privacy issues, while seniors are more likely than those 50-64 years old to cite computer issues, according the AP-CNBC poll.
About three-quarters of seniors are not on Facebook. By contrast, more than half of those under 35 use it every day.