UsageDetails.aspx and SPUsageWeb.aspx (why some sites show UsageDetails.aspx and not SPUsageWeb.aspx)

One of my colleague happen to ask a question (that his customer asked him) about the Site Usage Reporting and logging in Central Admin. Basically some of his site were going to following URL and some of the other sites were going to the 2nd URL when they click on Site Usage Reporting under Site-settings link:

1. http://moss.litwareinc.com/site1/_layouts/usageDetails.aspx

2.

http://moss.litwareinc.com/site2/_layouts/SpUsageWeb.aspx

The reason for this is some of the sites have following 2 features under the (Site Features) disabled:

a. Office SharePoint Server Enterprise Site features

b. Office SharePoint Server Standard Site features

Basically if you are using plain WSS then you would see the usageDetails.aspx page for usage reporting and if you are using MOSS (Sharepoint 2007) with both STD and ENT features enabled then you would be directed to the SpUsageWeb.aspx page.

Thanks to JoJo (my friend and colleague) for raising this query (as this was the same thing that I was asked a lot of times by my customers when they had both WSS and MOSS implementations and often there was a comparison :) WHY that site show a nice charted report copared to my report which lists only some list with some numbers but no charts.