Spam refers to electronic junk mail or junk newsgroup postings. Some people define spam even more generally as any unsolicited e-mail. In addition to being a nuisance, spam also eats up a lot of Network bandwidth. Because the Internet is a public network, little can be done to prevent spam, just as it is impossible to prevent junk mail. However, the use of Software filters in e-mail programs can be used to remove most spam sent through e-mail.