Blacklisting
Blacklists are a very effective way of fighting spam. It affects the UCE vendors and deliverers directly. The domains that send masses of emails to addresses that do not exist or being rejected, because of the message contents (Hard/Soft Bounce) are being added to the blacklists. The email recipients Internet Service Providers (ISP’s) and Email Service Providers (ESP’s) match the sender domain and the landing page domains against the known blacklists to determine whether it is listed. If so, the email is being marked as spam.
To stop spammers crawl the web searching for email addresses, ISP’s, ESP’s and blacklist owners such as SPAMHAUS Project publish email addresses on random blogs (spam trap address). Those email addresses serve no other purpose than wait for emails to start coming in. Every message sent to those email addresses indicate that the email address was automatically scraped off the website in order to be marketed and the sender domain has to be blacklisted.
Blacklists are a powerful tool of cleaning the web of the unwanted mail. However this is a big problem for legitimate email marketing companies as this can affect their entire internal email delivery. Most blacklists take a long time to be cleared and often blacklist owners charge a fee for the domain to be de-listed.
