If you have ever "Liked" or have friends who have "Liked" a page then you are being targeted by Facebook's advertising. If you get irritated by those advertisements, there is something you can do about it. Written below is a further explanation of how Facebook uses your personal data to target your advertisements. But first here is how you put a spot to the company which has a market cap of over 200 million.
In your profile, click the upside-down triangle in the upper-right corner and then the "Settings" button.
Click on the "Ads" tab. The two options here are easy to switch and very powerful. For each one, click the "Edit" button and then "No one" instead of "Friends."
That's not hard, but before I sign off let me just give you a quick explanation of what "Ads and Friends" is really about. Facebook claims that it "doesn't sell your information to advertisers," but what it does do is put you in a group that the advertiser can browse.
If you and a friend a hobby, then Facebook will take note of that. If you mention a product or company advertising on Facebook, it will probably put it next to an advertisement that your friend will see. It's basically a testimonial, but not one you might want to make.