HONOLULU -- Facebook is the largest social networking site on the Web with more than 1 billion visits a month. The phenomenon is growing, but when is keeping up with your friends too much? Could you be a Facebook addict?

What started out as a networking tool strictly for college students now has more than 300 million active users. About half of them log on in any given day.

It is not just for kids. The fastest growing demographic is those 35 years and older.

More than 6 billion minutes are spent on the site each day worldwide, according to Facebook.

Are you sneaking a peek at your Facebook site at work, ignoring your kids, or checking the Facebook site while driving?

"I'm on Facebook about two to three times an hour," Mona Sumibcay said.

Sumibcay admits she is addicted.

"Sometimes there's no purpose really for me getting on it. I just got on it 5 minutes ago and now I feel the need to get on it again to see what's the new update," she said.

The 24-year-old graduate student has been a Facebook member from when it started in 2004. Sumibcay said it is her primary tool for communicating with friends and family.

"I have about 1,100 friends. Which are all mainly from school and high school friends and family members," she said.

Sumibcay said she has put off schoolwork to chat with friends on Facebook.

"It's just a really great distraction," she said.

Sumibcay is not alone. The average user has 130 friends on the site and more than 10 million users become fans of pages every day, according to Facebook.

Its popularity is exploding worldwide with more than 200 million users.

There are even videos on YouTube about how to check Facebook at work without getting caught.

People who use Facebook on their mobile devices are almost two times more active on Facebook than non-mobile users.

Antique and jewelry business owner Brenda Reichel is connected to Facebook 24-7 thanks to her Blackberry.

"I've been known to glance at it even with a client in front of me," Reichel said.

Reichel said she uses Facebook to connect with friends and clients for work.

"It doesn't really interrupt anything per se because I own the business, but I probably would've fired myself," she said.

Although there are no statistics on Facebook addiction, and there are no real documented cases of it locally, it is not a far stretch to go from social networking to social dysfunction, psychologist Dr. Martin Johnson said.

Johnson compared an addiction to Facebook to other addictions where compulsive behavior takes over your life.

"Once you're in an addictive cycle, there's a tendency to be doing that behavior whether it's Facebook or anything else to exclusion of anything that you need to be doing, also to the exclusion of things that you used to enjoy doing," Johnson said.

Finding yourself doing less of other hobbies, spending less time with friends or family or having people tell you directly could be signs of addiction.

"When people are having trouble stopping when they're no longer enjoying it, but they feel they have little choice. When they're doing this behavior to substitute or it's interfering with work, family, friends, and they're having trouble stopping on their own, that's a time to seek help," Johnson said.

Both Sumibcay and Reichel said Facebook has helped their friendships and improved business. They said they are having too much fun for it to be a problem.

"I think anyone in today's market, if they don't take advantage of every form of media available, I think they're definitely missing the next generations," Reichel said.

Johnson said he finds nothing inherently wrong with networking site. However, he said it is a superficial form of interaction and should only augment the friendships we have in real life.