A botnet is a group of compromised computers—often a large group—under the command and control of a malicious botmaster. Botnets can be used for a wide variety of malicious attacks, including spamming, distributed denial of service, and identity theft. Botnets are generally recognized as a serious threat on the Internet. This paper discusses SocialNetworkingBot, a botnet we have developed that uses Twitter for command and control. In SocialNetworkingBot, the botmaster tweets commands that are acted on by the individual bots. We discuss the functionality and implementation of SocialNetworkingBot, as well as a small-scale experiment that we have conducted. The botnet presented here is intended to serve as a proof of concept and a platform to facilitate further research.