There's no stats page but last I checked it was around 5M monthly unique users (depending on how you count them), perhaps 10M page views a day (including a guess at API traffic), and something like 1300 submissions (stories) and 13k comments a day.
The most interesting number is the 1300 submissions because that hasn't grown since 2011 - it just fluctuates. Everything else has been growing more or less linearly for a long time, which is how we like it.
Thanks dang. Submissions not growing could mean the the users are already finding and submitting most of the interesting stories out there, and there's not much more to find.