You have willingly told Facebook who your friends are, what your hobbies are, how old you are, where you live and whether you are in a relationship or not. What's more, Facebook knows what you like and dislike, what your interests are, what your favourite movies and songs are - simply from the updates you share and the 'like' buttons you press. The big question is: are you happy for Facebook to exploit what they know about you?

The entire Facebook business model is based on the effective use of your data. Here is the deal: they give you a free social media platform to use and in turn sell advertising and insights based on what they learn about you. Today, Facebook has massive capabilities to collect, store and analyse data - what we call 'big data analytics'. This allows Facebook to sell very targeted advertising - e.g. 'someone living in the Mid-town district of Manhattan, who is single and who is interested in baseball and likes pizza'. This kind of knowledge is a marketeer's dream!

But Facebook goes beyond simply analysing and 'mining' the user profile data you have shared and the up-dates you have written. USA Today revealed how Facebook tracks you across the Web. Basically, when you create an account, Facebook inserts a 'tracking cookie' into your Web browser that allows Facebook to track each website you are visiting. This means when you are logged into Facebook and then browse the web (completely separately from your Facebook activities) Facebook knows what sites you are visiting.

There's more: Cnet reports that whenever you click a Facebook 'like' button on any website, your preference is not only shared with your friends and on your profile, but data about your interests is sent back to Facebook's servers - ready to be provided or sold to their advertising partners. What's more, personal data is exchanged when you use apps like FarmVille or Words with Friends via Facebook. It has even been reported that signing up for these apps will give those companies who created the apps access to your personal data - even details you specifically told Facebook to keep private.

One more: Facebook has also invested in image processing and 'face recognition' capabilities, that basically allow Facebook to track you - because it knows what you and your friends look like from the photos you have shared. It can now search the Internet and all other Facebook profiles to find pictures of you and your friends. Face recognition allows Facebook to make 'tag suggestions' for people on photos you have uploaded but it is mind boggling what else they could do with technology like that. Just imagine how Facebook could use computer algorythms to track your body shape. They could analyse your latest beach shots you have shared and compare them with older ones to detect that you have put on some weight. It could then sell this information to a slimming club in your area who can place an ad on your facebook page. Scary?
Here are my questions: Are you comfortable with Facebook using your data? Maybe you see it as a step forward where Facebook can find your long-lost friends and you like the fact that Facebook can recommend relevant products and services. Or does this all feel a little too much like 'Big Brother is watching you'? Do you see it as an intrusion of your privacy and does it scare you that Facebook knows everything about you and could exploit and sell what it knows? Does this make Facebook too powerful? What do you think? Share your views...
Here are ways to better protect your privacy:

1. You can tighten your settings security settings on your Facebook account. Here is a great list of the top ten must-know security settings for Facebook.
2. You can download software to block all tracking activities of your web searches or make any tracking attempts visible. Two tools to look at are Ghostery and DoNotTrackMe
3. You can use the 'InPrivate' mode of Internet Explorer, the 'incognito' browsing when you use Google's Chrome or 'private browsing' option in Safari. This will disable the browsers to store information about your web searches.
4. You have to read the terms and conditions of any apps you download and use. You can check the privacy scores of any current Facebook apps using tools like PrivacyFix