Here is the exact online business model that I follow that will always work, is sustainable, and is scalable:
You start by setting up a niche site >
you create 10-20 content pages >
you write 20 articles based on your content pages and you submit them to article directories and document-sharing sites >
you build high quality back links to your site and the different pages >
you test different monetization strategies such as adsense, digital products(Clickbank), or physical products(Amazon) >
you setup a freebie people will get for giving you their email address >
you have an autoresponder series of 10-20 emails that each subscriber will be sent that further informs/sells your product(s) >
you setup another niche site following the same format >
you do this until you have 4 or 5 niche sites >
you go back and analyze which niche site is performing the best >
you create your own product for that niche site, this can be an ebook or membership site(I highly recommend a membership site) >
build more pages and move towards making the site an authority site >
this whole time you keep setting up at least one new niche site per month >
keep turning your best performing niche sites into authority sites, or at least a site with your own product or paid membership >
if you want a FAT, one-time check, then consider selling one of your authority sites on flippa >
some of the niche sites that you've created that you're not interested in developing further can also be sold for decent sums on flippa >
enjoy the hell out your online empire.
The point is, if you can get your first few niche sites making money, then you've learned enough about traffic, monetization, and conversion to replicate your results on a bigger scale, and with your own products.
The sky is the limit after that.