Sales-Age
It's simple. With a site name like "Gaming Age" and the url gaming-age.com (at least in the pre-NeoGAF days), it quickly became a common thing to attach "-age" to a topic of discussion. Car-Age, whatever. Sales-Age is just one of the few that's ended up in permanent use to describe the sales discussions that go on.
Also notable that Gahiggidy owns the [1] domain. There's nothing on it as of this writing, but thanks to the Internet Archive its old form can still be seen.