The Internet is not a place where privacy is respected. When it comes to social network sites where you and your associates are constantly volunteering personal information and images, you need to be extra cautious. The implications could be far reaching and at times disastrous, to both your work and personal life. So log into your Facebook (FB) account right now.
Go to Settings and then Privacy and examine each subsection: Profile Information, Contact Information, and Search etc. You will be able to control who can see your profile, post to your wall, contact you, what information is available to Facebook-enhanced applications and websites and who can see your FB
etc. Avoid the "Everyone" setting everywhere. Don't accept Facebook's recommended settings. Unless you want your life to be an open book, of course. If you leave it at that, everything you post -- status, image, or link, will be visible to not just everyone of Facebook's 350 million users but also search engines like Google. By and large, and if in doubt, stick to "friends only". Don't add-on FB applications with careless impunity. Once you allow an application in, it has access to your account/profile and this can always be misused by that company. Which is why it is also vital that you don't skip the much ignored Applications and Websites section of Privacy Settings. Go to Settings > Privacy Settings > Applications and Websites, then "What your friends can share about you - Edit Settings:" You can't hide the photos other people put up of you or tag, but you can restrict the audience to Only Friends. Go to Settings > Privacy Settings > Profile Information and tweak "Photos and Videos of me." If you don't want your phone number to be passed around among little people, please don't put it up on Facebook. The people within your immediate circle who matter will have it anyway. And the ones who need it, can send message you for it.
If career is important to you avoid flaming your boss or work place on FB. You never know, something harmless today could well result in a lost job opportunity tomorrow. So, do this today. It won't take you more the 10-15 minutes but it could save you lifetime of heartache. If you are really in a soup, you can resort to a programme called Web 2.0 Suicide Machine (www.suicidemachine.org) to eradicate your entire existence from Facebook -- or even Twitter, LinkedIn, etc. But that's the last resort.