News flash: I’ve been thinking. Shocking, I know… actually not at all. But, silly jokes aside, I’ve been thinking that it’s long past time I mention one of the “projects” that’s been taking up a fair amount of my time for the past few months: Physics Stack Exchange.

This week marks 100 days since the Stack Exchange network launched a Q&A site on physics. I’ve been involved essentially since the site first opened up, and in fact I’d been hoping for a site like this to take off ever since the first time the Stack Overflow team first proposed opening up the SO engine to other topics besides computer programming, back in 2009. If you look at traditional forum-based physics Q&A sites, like Physics Forums, a lot of topics turn into extended discussions as the participants try to hash out all the minor details. That discussion has its place, but most of the time, when you ask a question, you just want to get the right answer. And on Stack Exchange sites, that’s exactly what you get: the first thing listed after a question is the highest voted answer. So I was optimistic at the outset that physics.SE (as we call it) could go a long way toward elevating the good answers in the world of Q&A above the cruft.

With just over 100 days of experience to draw on, how well has it worked? Not too badly, I suppose. The site gets a steady flow of new questions, and most of them get pretty decent answers, all while we’ve managed to avoid pseudoscience and crackpot self-promotion. Area 51, the new site staging zone, hosts a summary of relevant statistics, and as I write this, it reports that we have 15.9 questions and over 1500 visits per day, plus 97% of questions answered with an average of 2.8 answers per question — “excellent” by Area 51 standards on all counts. In comparison to other Stack Exchange sites, that probably means we’re doing reasonably well.

On the other hand, Physics Stack Exchange is still stuck in many people’s minds as a student-level site. This is not an issue because of a lack of quality in the answers we’re getting; there are at least a few users (well, mostly one) who consistently provide correct answers to most people’s questions. It’s more an issue of a deficiency in the scope of the questions we’re able to deal with: a lot of research-level questions can’t be properly handled on physics.SE because we don’t have a critical mass of researchers able to answer them. That happened because most of the researchers saw that in the early days of the site, it was being dominated by less advanced questions and answers, so they left to set up their own proposal. To this day, there is still some debate about whether this split is a good idea, but it definitely limits our ability to bring in new participants — recruiting is hard when you can’t even be sure who your audience is.

Where do we go from here? I think the biggest issue facing this site has been, and continues to be, publicity. For most other Stack Exchange sites, the growth in the level of participation has been exponential, but physics.SE has seen basically no growth at all, except for a single bump when we were linked from Cosmic Variance. So obviously we need to investigate better recruiting techniques if the site is going to be viable. We’ve made a promising start and it would be a shame to see all that just fade away.