It's not a separate long process because there's only one decision maker. You basically need a good landing page and a working product's demo. Sometimes a client asks a question in support before a purchase but most of the purchases are without direct communication.
What would sales do in a B2C shop? In my mind you just create a product people want, slap AdWords on it for revenue and add a marketing team for growth. I have a hard time imagining what for example Reddit would do with a sales team.
Edit: Apparently Reddit have a sales team since they have their own ads platform, they wouldn't need it if they used AdWords.
This makes more sense in the context of the GP comment if Reddit's ad network is found on sites outside of Reddit. I confess ignorance to these particulars.
