I have a question about the license agreement in regards to the following section :

7. NO RESALE OF SERVICE

You agree not to sell, resell, or offer for any commercial purposes, any portion of the the XOOPS Sites, use of the the XOOPS Sites, or access to the the XOOPS Sites.

Now i understand that this criteria is explaining that you can sell the XOOPS package for your own commercial gain (or areas/modules etc).

However are you able to use XOOPS as a commercial tool in which users pay for content (such as advertising)?

"the XOOPS Sites" are www.xoops.org, modules.xoops.org, themes.xoops.org and dev.xoops.org - not your own personal or commercial sites

What this means is that you may not e.g. put links to www.xoops.org in a payment-only section of your business links

There are no restrictions to what you can or cannot charge for on your own sites.