The yelp campaign uses a more funny approach by placing the people in different situations that in which case will convince  them to use their app to get them out of this horrible situations. I think this approach works really well in getting the audience to use their apps because no one would like to be stuck in any of those kind of situations. In the other had the foursquare advertisement is a bit more straight forward basically telling their audience that they can find anything according to their personal preference. Both Ads work well.