That's a good observation. However, only a few job posts mention git, even though it's probably used by most companies. I would assume the reason is that git is pretty easy to learn in 1 or 2 days (at least the basic functionality) and programmers shouldn't be rejected based on that.
If you use a fake email to signup, then you probably aren't that interested in that service. We curate signups, so that only the relevant ones are displayed on the Sunnytrail dashboard.
If there's no info about an email address, then we display info about the domain.
You have to put a javascript on your registration page and then you see all your new signups in a realtime dashboard with added social context, like the screenshot on the home page. You also get email alerts whenever someone who is really influential signs up.
There is also the option of calling a REST api to send us new signups.