Spam is flooding the Internet with many copies of the same message, in an attempt to force the message on people who would not otherwise choose to look at it twice! Most spam is advertising, often for dubious products, as it costs the sender very little to send. Email spam targets individual users with direct mass mail messages. Email spam lists are often created by scanning Usenet postings, stealing Internet mailing lists, or searching the Web for addresses. One particularly nasty variant of email spam is sending spam to mailing lists (public or private email discussion forums.) Mailing lists limit activity to their subscribers, spammers will use automated tools to subscribe to as many mailing lists as possible, so that they can grab the lists of email addresses!