Those stats are only about Glass 2.0, which is in a very limited early beta. Those two users are me and my alt. We have about 300-350 users on our live version, which doesn't report back version data in the same way as the beta, so it's counted elsewhere.
Nexus has done most of the work on the builds section of Glass, but the backend is just as complete as the add-ons side, if not more. Everything left is mostly aesthetic and just front-ended. I do plan on eventually integrating it in-game, allowing you to download and upload builds from ingame, as well as send and share them.
The new Glass site is completely open source of github, you'll find a lot of the meat of the site in private/class/ if you want to take a look.
Edit: just checked, actually upward of 400 users.