Courtney Purvin got a shock when she visited Facebook last month. The site was suggesting that she get back in touch with an old family friend who played piano at her wedding four years ago.
The friend had died in April.
“It kind of freaked me out a bit,” she said. “It was like he was coming back from the dead.”
Facebook, the world’s biggest social network, knows a lot about its roughly 500 million members. Its software is quick to offer helpful nudges about things like imminent birthdays and friends you have not contacted in a while. But the company has had trouble automating the task of figuring out when one of its users has died.
That can lead to some disturbing or just plain weird moments for Facebook users as the site keeps on shuffling a dead friend through its social algorithms.
Facebook says it has been grappling with how to handle the ghosts in its machine but acknowledges that it has not found a good solution.
“It’s a very sensitive topic,” said Meredith Chin, a company spokeswoman, “and, of course, seeing deceased friends pop up can be painful.” Given the site’s size, “and people passing away every day, we’re never going to be perfect at catching it,” she added.
James E. Katz, a professor of communications at Rutgers University, said the company was experiencing “a coming-of-age problem.”
“So many of Facebook’s early users were young, and death was rare and unduly tragic,” Mr. Katz said.
Now, people over 65 are adopting Facebook at a faster pace than any other age group, with 6.5 million signing up in May alone, three times as many as in May 2009, according to the research firm comScore. People over 65, of course, also have the country’s highest mortality rate, so the problem is only going to get worse.
Tamu Townsend, a 37-year-old technical writer in Montreal, said she regularly received prompts to connect with acquaintances and friends who had died.