Interesting post nuf-ced, just want to add on the profit margin & accounting side of things. When you are evaluating your margins make sure that you are evaluating your cost as accurately as possible, what I mean by this is that if you hire someone to work on a product for you, you should have a portion of their salary/wages (unless of course this person would be working for you regardless - this would be a fixed cost) are being allocated to the cost of the product.
For example, If I was to create a network of sites I would need to pay for the domain & hosting say, $11.00 (variable cost - it is dependent on the number of websites created), a portion of the workers expense (say the worker can create content on 2 sites an hour, and you pay them $14.00/hour, you would allocate $7.00 to your variable-cost/website).
Essentially your cost per site would be:
Domain & Hosting: $11.00
Content: $7.00
Total/site: $18.00
And lets say we sell each site for $50.00.
Your Profit Margin would be:
Sell Price: $50.00
Variable Costs: 18.00
Profit Margin: 32.00
Profit Margin % - 64%
Definitions:
Fixed Cost - An expense which you would have regardless of the product you would be creating.
Variable Cost - A cost associated with the production of each unit made, it is dependent on the number of units made.
Hope this helps.