A more thorough explanation:

Vicarious infringement is a type of secondary liability for direct infringement. This means that a person can be held responsible for someone else's infringement if they had the power to control the infringing activity and had a financial interest in it. The person does not need to have known about the infringement or intended for it to happen.

For example, if a company hires someone to create a website for them and that website infringes on someone else's copyright, the company could be held vicariously liable for the infringement because they had control over the website and a financial interest in it.

The concept of vicarious infringement is important in cases involving both copyright and trademark infringement. However, cases involving trademark infringement often require a higher level of control or involvement in the infringing activity than cases involving copyright infringement.

In recent years, the concept of vicarious infringement has become particularly relevant in the context of the internet. For example, in the case of Metro-Goldwyn-Mayer Studios Inc. v. Grokster Ltd., the Supreme Court found that Grokster, a file-sharing service, could be held vicariously liable for the copyright infringement committed by its users because it had the power to control the infringing activity and had a financial interest in it.