The typical customers of such a service are university and college students. Universities and colleges may investigate papers suspected to be from an essay mill by using Internet plagiarism detection software, which compares essays against a database of known essay mill essays and by orally testing students on the contents of their papers. In response, many essay mills state that a unique essay will be composed by a ghost author and pre-screened with plagiarism detection software before delivery, and as such will be undetectable as an essay mill product.
'Essay mill' companies hire university students, graduates, and professional writers to ghostwrite essays and term papers, and solicit business from university and college students by posting advertisements. Until the early 1990s, most essay mill companies were 'bricks and mortar' businesses offering their services by mail-order or from offices located in university or college towns. By the 2000s, most essay mill businesses have switched to an e-commerce business model, soliciting business and selling essays using an Internet website. Companies often provide free sample essays on popular topics, such as Hamlet or The Merchant of Venice, to attract Internet searches.[citation needed]
The most basic 'essay mill' service is the sale of a previously-written essay; services advertise essays that have allegedly gained a good grade and which have allegedly not been used for plagiarism before. Students using essay mill services have little or no legal recourse if the essay they purchase does not actually receive a good grade.
Since submitting a previously-written essay exposes a student to the risk of detection, some students will pay a much