What is the main advantage of using e-mail to complain about a service or product?

Unlike conventional mail, email can send your complaint within minutes or seconds to the company.  This is the reason why use of email has become popular.  The reaction to act on the complaint will depend on the company.  Sending an email does not guarantee that they will act on it right away. 

answer; that person may have a larger tax bill to pay on income taxes;