I was looking at the Area 51 statistics for our site early today:
What stands out is the low average number of questions per day. We seem to be doing quite well on all other metrics but the 1.9 questions per day is disappointing and certainly not even remotely comparable to a site like eHam (while acknowledging the many foibles of that site).
My first reaction was that us "regulars" on the site should take the time to ask a question periodically. But this does not seem like a successful approach in itself since it would involve the top 25 reps posting a question every other day for a prolonged period.
The quality of the answers on this site is very good and the moderation is well done. What can we do to bring more pertinent questions to this site? And perhaps equally important is how do we do so without compromising the ethos of the site?
EDIT
Some data related to Kevin's answer regarding referrals, here are the referring sites statistics. It is not what I would have expected:
And in the last couple months, there has been an uptick of new questions. This is a weekly view: