How Do Spammers Obtain E-mail Addresses?

It is rather obvious that there are some ways through which spammers get e-mail addresses and cover the huge quantity of users all over the world:

• Website harvesting programs. Using special program tools spammers extract e-mail addresses from web site page HTML code and gather a single e-mail address warehouse.
• Dictionary based programs. Spammers often use these programs to generate e-mail addresses. Such programs combinate separate letters, words, numbers and symbols together so that to generate admissible e-mail names which are joined to a chosen e-mail service provider domain name so forming the whole e-mail addresses.
• Opt-in lists. Such lists store e-mail addresses of users who indirectly but voluntarily gave their agreement to that. That means the users accepted the offer to be subscribers and agreed to add their e-mail addresses to mailing list. Commonly opt-in lists are organized as records within a database. So dishonest employees who somehow have an access to such a database may sell it to spammers via Internet or on CD-ROM.
• Forums and interactive web sites. When you post your email address to the Web to sign up for a discussion forum and forget to hide it from public eyes, you expose yourself to spammers who are among the forum registered users as well.
• Email forwarding. If you forward an email to many people, make sure you send it to yourself in the To: field and put everyone else in the Bcc: field. Bcc means blind carbon copy. It's used to send a copy of the email to someone without revealing his or her e-mail address to others who are going to receive the copy too. If you use the Cc: field instead you expose everyone's e-mail address to a lot of other people. If you are not that careful, you may accidentally include a spammer e-mail address into the Cc: field becoming this way an indirect accessory of the spam distribution.
• Public WHOIS database. When a company or an individual registers a domain name, the Internet Corporation for Assigned Names and Numbers requires the domain name registrar to submit the company/individual personal contact information, including the e-mail addresses of people that are in charge of technical issues, to the WHOIS database. Once such information appears in this online database, it is publicly available to spammers who take e-mail addresses out of it using the WHOIS utility. To prevent spammers from that it is preferable to keep domain name information in private WHOIS database, commonly this service requires a small monthly fee to be paid.