Email is a great way to communicate with customers and prospects. However, not managing a database of email addresses for accuracy and eliminating disabled or inactive email addresses from these lists can be disastrous.
Sending emails, whether it's newsletters, account information, or any other standard customer or prospect communication, to invalid or disabled email addresses, if done frequently enough, can land you on spam lists. This means that your important communications to working, legitimate email addresses will land in the spam folder and likely go unread.
How can this happen? People change email address all of the time. They leave companies, or create temporary email addresses for certain purposes, or just simply start getting too much spam so they create a new email address and disable the old one.
If you continue to send email to addresses that are not valid frequently enough, ISPs (Internet Service Providers) that host these email addresses can and will put you on their spammer list under the assumption that you are sending email to random addresses. They will then block all of the email you send in the future to any other email accounts they host. This can severely hamper your marketing and customer communication efforts, so maintaining clean email address databases is very important. Also, once you are on a spammer list, it can be very difficult to get off.
Syntax checking email addresses alone is not enough. It's important to know whether or not the email address can receive emails and not get bounced back. After all, the syntax of a disabled email address will likely be correct. This is where a sophisiticated email address verification process that employs multiple algorithms and online mechanisms is important and useful.
A scan of all email addresses prior to outbound communication (or at least at some regularly scheduled interval) to verify validity, and then removing those email addresses that are no longer receiving email, is now an imperative for an effective communications program.