I think Facebook Ads is the most popular paid social media advertising. I mentioned the description beauty because I saw how Facebook would push your paid ads on the timeline. The ad will be posted with a line on top that says it was "liked" by A and B - those are the names of your Facebook friends. But more likely friend A and friend B do not even know about that Facebook ad. I was asked by an uncle about an ad where he saw my name that liked the post. I was surprised so I made my own observation and true enough Facebook does that trick.