As webmasters and database administrators struggle to keep email address databases clean, web site form validation becomes key. At this point, the state of email address validation is poor. Feel free to prove it to yourself: go to your favorite site that requires registration, and enter “dlkjfdklj@djflkjdlkj.com” as your email address. More often than not, it will let you through no problem. Keep in mind that not only is it letting you through, but it is also storing that email address in an internal database. These email databases get littered with bad addresses, which companies usually handle in one of two ways:

• Ignore the problem and send membership emails anyway. This results in many bounced emails that waste bandwidth both to (when sent) and from (when returned) the Internet.
• Hire temps to painstakingly pick out individual bad email addresses. This is a costly and time-consuming endeavor. Additionally, this is a reactive, not proactive, solution.

What you should be thinking at this point is “Why not stop the bad email address before it gets into your database?” As you might guess, there are different approaches to validating email addresses on web site forms. Generally, there is an inverse relationship between ease of implementation and quality of validation. However, with the recent popularity of developer components, these types of solutions can typically be “snapped in” with little learning curve.

The following is an overview of the various levels of email address validation.