This usually happens when you've allowed an app access to your Facebook profile without realising it. Many quizzes and interactive pages ask you to "log in with Facebook". It's worth taking the time to see what permissions the app is asking for. Nearly all will want to know who your friends are and where you live. They'll take this directly from the information you've provided on your profile. In order to post the results, from quizzes and similar content, the app will need to be able to publish stuff onto your wall - which means it can write things on your behalf. A lot of the time this isn't a problem, most apps you use are "only" after your data so they can sell it. It's when the odd rogue app starts posting advertising onto your wall that problems arise.
So if your page is suddenly trying to sell viagra or acai berries to your friends, what do you do?
The first, and most important thing to do is to change your password! Please don't recycle passwords that you use elsewhere. A shiny, new password is what is required. Try and include a number or some non letter characters to make it more secure. Oh, and just putting a number 1 on the end of your password (or an exclamation mark) is too easy to guess - get a bit more creative.
The second thing to do is to check what applications have access to your Facebook account. If you're a keen quiz taker you may be shocked at who can see all your information!
The second, and far less frequent, issue I see with Facebook pages is when they are "cloned". This means that someone has copied your profile picture and information onto a new account and then they start sending friend requests out to loads of other people - often including your own Facebook friends. These cloned accounts are most often used in "like farming", but they can occasionally be used maliciously. By pretending to be you, the person in control of the cloned account can make it seem as if you are posting offensive and upsetting content. This can be particularly problematic if they do things like using the cloned account to leave offensive comments on your employer's Facebook page....
What can you do if you find someone has cloned your account?
You need to report the rogue account to Facebook. This can be a long and drawn out process. You will often need to provide scanned copies of documents to prove your identity. Perseverance is key here!
In conclusion:
- Be careful where you click.
- Change your password regularly.
- Check what apps have access to your account.