"Could you enlighten me as to the mechanics?
If my contract says I'll be paid monthly on the 15th, when do
I send in the invoice? Are the payment terms net-10, net-30, or longer?
Do I need to break out sick or vacation days as its own line item? What about the deductions?"
If you are having difficulty grasping this - you should not work for an early stage startup that is pre-funding. You are expecting very standard 'employeeship'.
If you are an 'employee' of the company - yes - you are required to be paid with W2's etc. - of course.
But if you're not obligated to be an employee of a company to accept equity - or other kinds of payment for services rendered.
As far as 'invoicing' - either you're being sarcastic or you've never done such a thing. You send an invoice, and you get paid. You have to claim it yourself in terms of taxation. As far as 'terms' - I'm hoping you are kidding. Either you get paid or you don't.
The company in this article I think was well past the time wherein they should have had had payroll set up - no doubt about it.
At the same time - it's absurd how confused many of you seem to be about the simple mechanics of getting paid.
You do not need a payroll system (i.e. W2s) while you are in the most early stages of a company.