Re: Just wondering...
Answer questions, mostly. What makes the product different? What's support like? Do they have any existing customers with similar configurations? They then serve as a point of contact when there are issues or the customer wants another unit/upgrades/etc.
The sales guys also spend a lot of time training the channel partners so that they know enough about the product to answer questions/sell the boxes as well as to ensure channel partners are up on the technical side of things enough to provide tier 1 and tier 2 support. (With tier 3 typically going back to the startup's engineers.)
Sales - especially being a sales executive - in a startup is a thankless, miserable job. It's hard work, spectacularly long hours, way too many conventions and so much travel you almost never see your family. Your friends become simply "the people you see most often in your travels", from "that guy" who seems to be on 30% of your flights to the sales guys for competing companies, to the "thought leaders" you keep seeing at all the VMUGs and conferences.
Sales guys have to coordinate with social media nerds, stay on top of social media (as it is increasingly used to try to talk with companies) and at the executive layer they have to work closely with all the other tentacles of the company to ensure that A) they know what's changing and B) they manage to push those changes/training down to their army of salespeople and channel partners.
Often too, salespeople are the front line for abuse. If a change happens to the privacy policy, pricing, whatever, it's the salespeople who serve as lightning rod. This is perhaps an important factor of their job: serving as lightning rod and insulating the engineers from the din and roar.
At the same time, they need to collect metrics on demand for the product. Who likes it? Why? Who doesn't? Why? What are some sales lost? Why are others won? What are customers demanding? Etc. Not just a "feel", but hard, empirical data. Taking that back to rest of the team and either tweaking marketing or product design.