[Computer Corner]

This is, as you said, an unfortunate price you pay for using Facebook. Advertisements are the main way that they finance and keep Facebook free for everybody. However, when you 'unlike' an ad, it will remember that and try not to show ads of the same type that you have previously unliked. The idea for this is so that if you unliked ads that you're not interested in, you will get ads that people are more likely will be interested in, and Facebook can charge more money for them.