I have been unsuccessful seeking a list of average gross/net profits
for different types of web-based businesses. Ideally I could compare
various categories by profitability from the answer or resources. For
example here are some ficticious numbers:

GOODS - Net/Gross Profit
Apparel: 10%/55%
Sporting Goods: 8%/32%
Software: 38%/90%
Books: 10%/30%

SERVICES - Net/Gross Profit
Web Hosting: 10%/55%
Email Services: 8%/32%
Ezines: 38%/90%
Advertising: 10%/30%

I am interested in as many categories as you could find, the more
detailed the better. This information would be valuable for me to
determine online profit niches that coorelate with my personal
interests/experience. Goods and services that are not being offered
online would be of interest too, but it's likely that most viable
models have been tried online.

Thank you for your help.