This is the most crucial part of the entire transaction; yet, in that instant when the user trusted your site the most, the site failed to work--or so the user believes.

What happened? Maybe the user put in the wrong expiration date or forgot to enter a phone number. It could have even been your server's fault.

The point is, without a good plan for error handling and usability, the user will probably never know what the problem is. When that happens, you can almost guarantee that you've lost a customer.

So how are you handling errors on your Web properties? Here are some guidelines to help you keep your customers happy.

What is error handling?

Error handling is the understanding that things don't always work perfectly. Therefore, an experienced error handler can anticipate when things go wrong and then predesign the appropriate and easy-to-understand error message and explanation needed to solve the problem.

For example: Your usability person may have noticed that 60 percent of Web users forgot to include their birth date when filling out the registration form on your Web site. With that knowledge, the person in charge of error handling can make sure to preemptively design and place a specific error message.

Make them see red

When we err, we expect to see the color red. From an early age, we learn to associate the color red with a correction. So when users do something wrong, they expect to see a glaring red indicator that tells them what they need to fix.

Just the facts, ma'am

Simply put, say what the problem is. Here's a good and bad example of an error message in which the user forgets to include his or her last name.

• Good example: "Last Name is missing from the required field."
  
• Bad example: "When filling out the form, you must put your first name and last name in for proper authentication."

Attempting to overexplain a simple issue can overwhelm and confuse the user. Remember the K-I-S-S method: Keep-It-Simple-Stupid!

Other error-handling tips

• What you might think is a user overreacting to a site problem is usually a crisis for the user.
  
• Try to explain the error well enough so that it doesn't happen again.
  
• Avoid technical jargon and acronyms.