Facebook is a social-networking database created by Harvard University student Mark Zuckerberg in early 2004. It now connects over 4 million college students at 1,500 campuses across the country.
"To our knowledge, we're available at all schools in the nation that distribute e-mail addresses to their student body," said Facebook spokesman Chris Hughes.
The site allows students to post a picture, list some personal and contact information and interests and keep a list of friends.
According to a statement from Facebook, about 60 percent of users log in every day, and they get over 100 million hits in any given 24-hour time period. Additionally, the statement said, about 16,000 new users sign up each day.
Dezeree Hodish, a 20-year-old student at the University of Pittsburgh, said she found Facebook to be a useful social and academic tool.
"I am able to connect with classmates to ask questions about homework," she said. "I can also use it to track updates of the clubs I am involved with on campus."
Polson Kanneth, a 2005 graduate of American University, similarly noted the academic benefit of Facebook.
"You can get in touch with people from class who you don't have the contact information for," he said. "It was great to see how people I haven't spoken to were doing" using Facebook.
Facebook recently expanded to high school students, a move Hughes called "the logical step to make."
"High schools and colleges, even though they're very different in a lot of ways, are ultimately built on the same concept: an educational institution around which students assemble their everyday lives," Hughes said.
"Facebook has been really popular at colleges," he added, "so we believed the same thing would be possible at high schools."
While the original Facebook required students to have e-mail addresses ending in ".edu" to sign up, the high school Facebook will require that students be invited by already-registered students in order to sign up.
Monica Rewiako, a student at Fordham University in New York, said she considers Facebook valuable to keep in touch with people she doesn't see often.
"I was able to get back in touch with people I hadn't spoken to since high school," she said.
Rewiako said she was not that concerned about the safety of her personal information on Facebook.
"Anyone at my school could have found that information through the school directory," she said.
Rewiako said she deliberately did not post her mobile-phone number on Facebook.
Hodish said she did not put her address or phone number on Facebook "because I didn't want random people to find that information. I am always concerned about putting my address on any published listing," she said. "Facebook was no different than other Web sites."
In addition to the picture and information listings, Facebook has an integrated messaging system for members to send notes to each other. Additionally, each user can turn on a "wall" where friends can leave public messages.
Facebook also notifies users of friends' upcoming birthdays and allows students to create and join groups based on any criteria they choose.
Kanneth said the groups are one engaging and fun part of Facebook.
"People come up with some strange groups," he said.
Among the most popular Facebook groups for American University students are ones declaring political affiliation and support for campus groups, as well as one group created for the express purpose of being the biggest Facebook group for the school (as of Wednesday it is the second biggest, behind a group for people who attended public high schools).
Hughes said the company is especially vigilant in safeguarding information because of the wealth of personal information held on Facebook servers.
"Safety and privacy are some of our top concerns," he said.