Think of traditional advertising where you might run an ad in a local magazine. You might have 5,000 people peruse that magazine, but maybe only 10% have any interest in the product or service that your business offers. With Facebook, through geo-targeting, interest targeting, and other laser targeting, your ad will only appear only in front of the ideal prospect for your service or products. So if your business sells solar panels, it would be like mailing the magazine to only the people who love energy efficient homes, and have an interest in solar products. Powerful. And each time someone “likes” something on their Facebook page, they are giving Facebook a tidbit of info about them. Each time they post something in their timeline about the “new solar panels on their roof,” they are telling Facebook about their targeting. So Facebook is continually gathering info about each member of Facebook, and this profile and targeting is used in Facebook marketing. So as a business owner looking to advertise, this is very useful info! And it’s all legal, as each person must agree to Facebook’s terms of service when they create a Facebook account. And it’s really a positive thing, as items of interest will continually show in a person’s feed.