I'm writing the product description for the business plan of my website and I'm looking for a proven structural template. My website is a mircodonation service (see my profile if your interested). The examples I can find via google are mainly for physical products or are just long texts which don't really offer any structre.
This what I've come up with so far:
First a High-Level Overview (but more detailed than the exec summary), which answers the question like Jarie suggested. Then I created a use case diagram, which shows all the relevant use cases. I then describe all use cases using bullet points. Finaly I created a chapter describing the technologies and services used.