While an S Corporation will pass through any NOL to its shareholders, those shareholders can use the NOL to offset their individual taxable income. So, if you have taxable income separate from your business entities, then you can use the S Corporation's NOL to offset your taxable income.
That said, in my opinion, the real benefit to a C corporation, as opposed to an S corporation (or an LLC), is that while corporation income is below $75,000 annually, the corporation's marginal tax rate is only 15%. As a physician, this may mean that you can retain earnings and net operating losses within the corporation, and offset each, while trying to grow the business.
The downside to this is that when you distribute the income, you will be taxed on the dividends as ordinary income -- which will increase your tax liability, unless you plan to retain the assets in the business until you retire, and you are in a lower tax bracket.
The asset protection value of the corporation may be more significant, if the online business has the potential to create liability which may extend into your personal assets, if you are sued. It's easier to defend a C corporation as a separate entity than an S corporation in court. So, if this is a concern, then a C corporation may be what you need to help protect yourself.
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