This is a name for what could be described as automated website visitors. What they are doing is to automatically visit hundreds or thousands of websites in a very short period of time to either just collect their content for what ever reason and/or to utilise their interactive components to keep the web server behind them busy. There is not necessarily a business reason behind those , but they do exist and each website owner needs to deal with their traffic or form submissions.
When booking a server on the internet, you either get a managed server, which is managed by the company that runs the data warehouse. Or you get a server (a.k.a. virtual host) with , which allows you and your IT staff to fully manage that server themselves and without limitations.