NEW YORK - Alicia Istanbul woke up one recent Wednesday to find herself locked out of the Facebook account she opened in 2007, one Facebook suddenly deemed fake.

The stay-at-home mom was cut off not only from her 330 friends, including many she had no other way of contacting, but also from the pages she had set up for the jewelry design business she runs from her Atlanta-area home.

Although Istanbul understands why Facebook insists on having real people behind real names for every account, she wonders why the online hangout didn't simply ask before acting.

"They should at least give you a warning, or at least give you the benefit of the doubt," she said. "I was on it all day. I had built my entire social network around it. That's what Facebook wants you to do."

Facebook's effort to purge its site of fake accounts, in the process knocking out some real people with unusual names, marks yet another challenge for the 5-year-old social network.

Having grown from a closed network available only to college students to a global social hub used by multiple generations, Facebook has worked over the years to shape its guidelines and features to fit its changing audience. But requiring people to sign up under their real name is part of what makes Facebook Facebook.

To make sure people can't set up accounts with fake names, the site has a long, constantly updated "blacklist" of names that people can't use. Those could either be ones that sound fake, like Batman, or names tied to current events, like Susan Boyle. While there are dozens of Susan Boyles on Facebook already, people who tried to sign up with that name after the 47-year-old woman became an unlikely singing sensation had more difficulty doing so.

Facebook spokesman Barry Schnitt acknowledged that Facebook does make mistakes on occasion, and he apologized for "any inconvenience." But he said situations like Istanbul's are very rare, and most accounts that are disabled for being fake really are.

"The vast, vast, vast majority of people we disable we never hear from again," he said. Because the exceptions are so rare, he said, prior notification is "not something we are doing right now."

Because Facebook has only about 850 employees worldwide, getting complaints answered can take a long time. Istanbul, whose father is from Istanbul, Turkey, said it took three weeks to get her account reinstated.

Without being able to log in for that time, she said she felt "completely cut off" from her contacts. Frustrated, she wrote e-mails, then mailed letters to 12 Facebook executives. To keep in touch with her friends and monitor her business pages, Istanbul said she sort of "hijacked" her husband's account.

"I think they just assume you can't have an interesting name," she said of Facebook. "I kept my maiden name because it's such an interesting name, I didn't want to give it up. And now I am having to defend my name."

Istanbul's sister, Lisa Istanbul Krikorian, also got locked out of her Facebook account, which she opened a year and a half ago. So she opened another one that omits her maiden name. Their mother and their cousin, who both joined the social network more recently, couldn't sign up under their real names.

© Copyright 2009 Globe Newspaper Company.