A bot-swarm attack is a form of cyberspace attack that uses numerous slaved devices or "bots" to send messages remotely.
A "bot" can be any network-connected device, be it a computer, a cellphone, or even a cybernetic implant.
These were initially used for Denial-Of-Service attacks to overload a comptuer's resources and force it to crash as a way of sabotaging a company. But in recent years, the "bot-swarm" system has been refined and used as a form of underground advertisement. Rather than overloading a company's network, the "bot-swarm" users use that company's media services such as message boards or forums or comment sections of web pages to send out multiple messages in manageable waves.