Hi Ava-
To add to Lisa's answer, there are lots of different types of SBI sites. Check out the case studies from SBI to learn more:
(not an affiliate link)
http://case-studies.sitesell.com/
Notice that "infopreneuring" is only one model.
One very successful SBIer sells medical equipment through his site - I don't believe he uses the store module - and he's doing multi-million dollar sales every year (granted, he's selling very expensive equipment!)
Depending on how you run your business (fulfillment, shopping cart, etc) you could use different models for your business. Affiliate links and advertising may only be a small part of your plan (if those figure in at all). That's up to you!