Cowboy Marketing

What Does Cowboy Marketing Mean?
A slang term to describe a situation in which a company is unaware that a marketer hired to produce legitimate opted-in email campaigns is actually using mass spam emails to promote the company's stock. This is a very unethical practice because marketers are often compensated with stock options, allowing them to capitalize on the unfounded demand they create for the stock they are promoting.

Investopedia explains Cowboy Marketing
This situation occurs when the marketer values its own interest over those of its client. Smart investors should not pay attention to spam emails and/or the stocks they promote. Buying these stocks will more often than not result in losing money because once the stock's price rises, the unscrupulous parties involved will cash out, causing it to plummet and leaving legitimate investors with losses.