We are aware this is a tougher topic than most to ask interesting and unique questions about. This factors into our graduation decision.
Of the 115 sites, History.SE is currently ranked at 72 by questions per day. It's ranked 74 by number of users and 67 by traffic. So it's right around where we'd expect it to be by the numbers. The recent self-evaluation (and my analysis of it) suggest that question about history are harder to ask than questions on other topics. Even so, questions do seem to get good traction on Google (~87% of traffic comes from search engines) and the quality of answers is generally higher other resources on the internet.
There are two ways to look at the data. Either:
- The number of users and traffic drive question rates, or
- The number of questions per day drives traffic and user participation.
The first is the most obvious mechanism since you can't have questions without people to ask them. So let's jump straight to the second:
Suppose you are a brand new user to History.SE. Maybe you came from another Stack Exchange site or maybe you found an answer to a question here when using a search engine. If the site looks good to you on first contact, you might start looking around. The obvious first place to start is the active questions page (which is where you go when you click "History beta" on the upper left of the page). Hopefully there are some interesting questions to read (such as Has there ever been a truly multi-sided war?, which was recently highlighted by the Stack Exchange Facebook account).
Ideally, a new user will find a few questions that are interesting and maybe be inspired to ask or answer one themselves. But it's probably more realistic to assume they will be distracted by a cat video someone posted somewhere else. If they ever come back, it would be helpful to see some fresh content. New answers on old questions can be helpful there, but the best thing would be a fresh question that the new user is interested in and might answer.
You can make a very similar argument for traffic with the big difference that it's Google, Bing, Yahoo, etc. who come back to visit the site. Search engines like fresh content since it's a sign the information is being curated. New pages (which is what a question represents to the rest of the internet) opens up new search keywords that help people discover the site. So the rate that new questions are asked correlates with the rate that search engines drive traffic our way.
Therefore the very best thing you can do for this site is to find an expert in history who needs an outlet for their writing. But the next best thing you can do is ask a great question every now and then. In many areas of life the Field of Dreams approach just won't work. People won't miraculously show up at your cornfield just because you built a ballpark there. But it can work on Stack Exchange. If several people decide to ask a question or two a week, you could probably raise the questions per day a noticeable amount. It might be a temporary effect, but you might catch the next great contributor on History.SE.
15 questions a day, by the way, isn't a scientifically determined number. Our current gut instinct (based on existing sites) is closer to 10 per day. Skeptics, which has the most restictions on participation, gets by with about 4 a day. One of the projects I'm currently working on is figuring out how much extra participation asking questions produces. I hope that among my findings will be more refined estimates of what question rate signals a healthy site.