Sorry about that. Was the 503 on GitLab.com (main application) or on the link in this discussion (monitor.gitlab.net)? The latter is to a public monitoring dashboard. It has been offline a couple of times today due to influx of traffic. We're closely monitoring it and attempting to keep it online. At the moment, GitLab.com itself has been absorbing the additional load, though. Let us know if you're seeing other issues.
I really like how the devs from gitlab are active on the HN thread and replying to people facing problems! Hardly see that with mature products anymore! Great going guys!