An unwanted, unsolicited e-mail, especially unsolicited commercial messages sent in bulk by organizations and people usually unknown to the receiver. (spamming refers to the process of sending this.) There is no agreed-upon definition of e-mail spam because it is in the eye of the individual beholder. Some argue that e-mail spam is the electronic equivalent of traditional junk mail, however it is much cheaper than junk mail. The cost of sending e-mail spam is very small, and people other than the sender pay most of the costs. The lack of significant barriers to entry (i.e. cost of sending) is often cited as a key problem with e-mail spam. It has bred a range of hucksters and fraudsters on the Internet. With traditional junk mail, a direct marketer must ensure that the offer and the response from customer targets are enough to offset the costs of mailing. With e-mail spam there is no such accountability. Spamming has been used unscrupulously to defraud online consumers. It is one of the negative by-products of the Internet age.