Some time ago I had talks with sales people from some of the major RDBMS vendors about this. They all differ in how they interpret the "user license" term. This is not only a problem when working with web server, but also a problem when working with middle-ware, like Tuxedo.

What they all have in common is that a user, is a person that benefits from their product. Then they differ in the exact way you are to pay for this. Some say, lets count the average user load during the day, some say lets count the maximum user load during peak hour.

My advice is that you contact your local sales person for an explanation of how they interpret this.

/brother t0mas