A service offered by cyber criminals that provides paying customers with distributed denial of service (DDoS) attack capabilities on demand. According to this article on eWeek, Booter services, or Booters, are "Web-based services that do DDoS for hire at very low prices and are very hard to take down."
Booters typically present potential customers with a Web front end that enables the end user to specify a Web site that they want the Booter service to target. Detecting and tracing Booters is complicated by the fact that the Internet service provider (ISP) that the Booter service appears to be hosted from is frequently not where the Booter is really located.
Booter services are frequently used by script kiddies and are responsible for many of the recent DDoS attacks that have received mainstream attention in the news.