(Originally published on meta Stack Exchange by Jon Ericson.)
Allow me to introduce you to Libraries & Information Science:
I've never visited the site myself and have no particular need to ask or answer questions there. (I do love libraries, but that's not really the point.) The above chart (visits per day for the last half year) comes from Quantcast, which has similar information about every site on the network. I'd like to draw your attention to a few details:
The site has a clear "heartbeat". Weekends and Christmas are clearly visible as people log in on Monday morning and start checking out (so to speak) on the weekends. This is a site with regular users.
Something big happened on November 27, 2012. I don't know what, but it really seems to have sparked new interest. Perhaps someone posted a link to a question on some site where librarians like to go?
There's a noticeable increase in activity over the last couple of months. We can see real growth in the site, though it's not explosive.
The Area 51 stats don't tell the full story. Is the site being used and curated or is it just a wasteland to frustrate future Googlers? Does the site have potential for growth or does it serve a dying subject? Are questions getting quality answers or is it mostly spam? These questions might be important to make a decision, but they can't be answered from the simplistic Area 51 stats. Looking at them can be a bit like calling for a pitcher to be fired because his batting average is so poor. (International version: Looking at them can be a bit like calling for a goaltender to be fired because he never scores any goals.)
Find a niche
It can be helpful to think of each site as a mini-startup. The first thing you need to do is make sure that you've got some market you can serve. Area 51 and the Community Managers do a pretty good job of ensuring that a site at least starts out with a vision of what sort of users it will attract. If you have regular users who care enough about the site to visit it week after week, you probably have found yourself a niche. For the chart above, I would guess that L&IS has found its place in the world.
Pick a growth strategy
The next step is to figure out how the site might grow. In business, it's possible your niche is too small (the old refrigerator salesman in Alaska gag). But on Stack Exchange, it's more likely that the segment of the market you are pursuing doesn't know about the site yet. This is doubly true if the site's subject is not particularly related to programming. Spikes in visits, such as what happened in the end of November on L&IS, signal that there is an untapped market waiting to be introduced to your site. If you turn up in search results or get mentioned by movers and shakers or get in the news, you might find visitors coming out of the woodwork.
Probably the most important step is to convince new users to stick around. Sites grow when the number of incoming users exceeds the number of outgoing (or rather not-returning) users. Maybe you saw a bunch of people turn up for the hat contest and then disappear. That would be a sign that you are doing a poor job of retention. You won't capture everyone who shows up on your doorstep, but a healthy site will find new users who quickly turn into site enthusiasts. Perhaps the best way to achieve this is by filling your niche well. (See above.)
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