Mashup games are always fun. Those built upon FourSquare have an extra layer of enjoyment, because they're tied to the real world. In the case of City Warfare, players use various water weaponry to soak other FourSquare users.
Security researchers have identified various vulnerabilities within the SoundCloud API that could have allowed attackers to gain access to user accounts and easily initiate DDoS attacks. Checkmarx Research conducted an investigation into the online social music platform.