This is the first in a series of three Tips that offer some thoughts regarding the emerging tools offered in the market for the Performance Management of web sites.

Probes aim to measure and view service direct from the end user perspective. This usually involves the download of an applet to the client to collect information. Data collected might include response time to access or download items, navigation paths through a web site, time outs and where the user chose to 'bail out' or leave the site.

The strength of this approach is the end user perspective on service. The response time to achieve certain tasks is observed as the user observes it.

Many users will consider the approach intrusive however, and dislike the idea of software being downloaded and run on their system. The response time information typically does not say where in the mix of servers and networks involved in the transaction any problems exist, when response times are below expectations. This approach therefore runs the danger of highlighting there is a problem but not helping with identifying what needs to be done about it. Correlating the end user view of the service with the processing data at key points such as the business servers is extremely time consuming and difficult.

Although often touted as 'performance' products, such probes actually offer little assistance to the performance manager. Much of the information gleaned, such as navigation routes and bailouts, is of more use to marketing departments or web site management teams. It helps us understand what users do on the web site, not necessarily if performance is poor and why.