The Internet has grown up. The Web is an integral part of doing business today. It’s no surprise, then, that companies devote billions of dollars every year to monitoring the software and hardware powering their Web sites. Outages, slowdowns, and other errors are costly—not only in lost revenue, but also in damage to customer loyalty and brand experience.

However, due to the increasing complexity of Web applications, tracing the source of Web site errors is getting more and more difficult. The applications powering Web sites, like all software, are plagued with bugs that quality assurance testing processes don’t catch. What’s more, current network and application monitoring tools simply aren’t up to the task of ensuring that every customer has a satisfactory experience. These tools, and the IT processes that have grown up around them, focus on application components, not on users’ actual experiences.

The surprise is that IT is not more aware of the problem. But how could they be, if the testing and monitoring tools they rely on are inadequate?

The focus of application monitoring and management, up to now, has been on availability: what percentage of time a Web application is up and running. More precisely, availability measures how often a Web application responds to a predetermined, automated test. But the tests that are currently used give no indication of whether the application is responding with the correct data, whether the user is able to get the information he or she needs, or whether customers are able to complete transactions or business processes.

In short, the tests can tell you if the lights are on—but not whether the store is actually open for business.

What’s needed is a simple shift in perspective. Instead of focusing on system and application performance, Real Availability should be focused on the actual experience of real users. The availability of a system must be measured from the perspective of the single constant and the final arbiter of success: the ability of your customers to conduct business. Real availability equals the percentage of successful user interactions with your site– from the user’s point of view.

Without being able to see what the Web application is delivering to the real end-user, there is no way to truly monitor if a Web application is functioning correctly. Assuming such a perspective can be difficult, but it is possible with the right tools. One such tool is TeaLeaf RealiTea, an application monitoring system that provides visibility into every single customer interaction, enabling you to correlate problematic sessions, quantify the impact, and quickly resolve real user problems.