The main source of e-mails for spammers comes from the web. Using e-mail collector programs, spammers can search the web for any e-mail addresses, whether on a personal web page, a business site, or other directory of public domain information.

Some spammers write programs to collect emails from newsgroups, where each distinct user is identified with his/her e-mail address. Some e-mail marketers may obtain a list of e-mails by purchasing it from another firm which requests e-mail addresses and other information when you sign up for their product/service online.