Less than three years ago, Facebook launched as a simple social-networking platform.

Today, with more than 140 million active users, it’s become much more.

The basic functions haven’t really changed, but the way people use Facebook is certainly evolving.

Facebook has become a snooping tool for parents, employers, spouses and even strangers. Although most people maintain protected profiles — meaning only accepted friends can view personal information — many users maintain open accounts, which allow anyone and everyone to browse all posted material, including status updates, photos, videos and discussions.

If you have a Facebook or Myspace account, locating you online is as simple as a Google search.

Nowadays, when young singles encounter a potential love interest, the first thing they do is to ‘creep’ through each other’s online profiles. Is he a smoker? A drinker? A womanizer? Check Facebook to find out all you need to know and more.

The easiest way to find incriminating evidence is to browse through photos and conversations. A quick cruise through an average guy’s Facebook profile will probably reveal a laundry list of ex-girlfriends and bad habits.

Employers often do the same kind of snooping with prospective hires. Even police and media now use Facebook as an investigation tool.

Often the biggest danger is not the stuff we post ourselves, but the comments and photos that other people display. If you are on Facebook and like to party on occasion, it’s almost certain that one of your friends have posted an embarrassing photo or two . . . or 10. Maybe you got caught on camera passed out with writing all over your face, or breaking out drunken dance moves at the office Christmas party?

A friend recently asked me if I thought it was unethical for he and his wife to investigate their daughter’s new boyfriend on Facebook.

My answer was, ‘Why not?’

The truth is, there is no ethical protocol to speak of. Any information posted to Facebook or any other social site is pretty much public domain.

Think of it this way: don’t post anything that you wouldn’t want your mother, spouse or boss to see, because at some point you will probably be judged by what’s been posted about you on Facebook.

The inescapable fact is, if you have a profile you are open to the unfortunate possibility that someone else might air your dirty laundry for you. If your nose is squeaky clean, I guess there’s nothing to fear. But come on, we all have those personal little somethings that just aren’t appropriate for public consumption.

At the risk of sounding like a high school health teacher, perhaps Facebook abstinence really is the best policy.

Here are a few mind-blowing statistics taken straight from Facebook’s online press room:

• More than 140 million active users

• Average user has 100 friends on the site

• 2.6 billion minutes are spent on Facebook each day (worldwide)

• More than 13 million users update their statuses at least once each day

• More than 700 million photos uploaded to the site each month

• More than four million videos uploaded each month

• More than 15 million pieces of content (web links, news stories, blog posts, notes, photos, etc.) shared each month

• More than two million events created each month

• More than 19 million active user groups exist on the site

• Facebook Wikipedia page