[jimnotgym]

Firstly accounting. Almost anything can be included in your margin (as long you are consistent). I think you atter talking more in terms of net- profit margin (all costs included) whereas fridaysoff seems to be talking about gross-profit (sales minus cost of the goods that you sold). As an online retailer I would suggest that you understand your gross-margin (how much you make on the product) separately from the costs of warehousing and shipping and separately from the overheads of accountancy, banking etc.

The reason for this is that by just summing your costs you louse sight of how various areas are performing, and you also lose the ability to compare. If you become a better buyer your gross margin improves, but by employing a picker it stays the same, however type warehousing costs do increase.

So in essence when most people say 'margin' they mean a simple sales-minus-cost-of-goods-sold.

Disclosure: I'm in finance at a retailer/wholesaler who is doing around 5x what the article is doing on ecommerce, it's smallest channel (about 1/20th of the company, but growing)