On the Hot Network Questions sidebar, there's almost always a Worldbuilding question there. However, a community like, say, Magento (picked at random), which apparently is almost 10x the size of Worldbuilding, I have never seen on the HNQ bar. So, why does Worldbuilding have such a disproportionate share of HNQ?
As TheSquareCubeLaw says, we're hot.
In practice it's because we interact, we're far more active. There are question and answers, the questions and answers get lots of votes. We know at a baseline that the HNQ is a self fulfilling prophesy that says if you're active you get more attention and more activity.
A quick glance over Magento, there's barely a question with a vote to its name, they're almost all on 0 bar a few, many don't have answers, or at best 1-2 answers, and even views barely into double figures.
A glance down our homepage and all the questions have votes, most into double figures, many have answers into double figures and views at least into triple figures with many into the thousands and more.
Apart from a couple of other similar stacks to ours, SciFi and RPG who also weigh heavily on HNQ, I suspect most stacks are more like Magento in their interaction levels. We're also more fun, and like SciFi and RPG, most people can at least understand what we're talking about. These are places you go for a bit of downtime, not more work.
Answering in worldbuilding is fun 90% of the time, a learning experience 5% of the time for one who answers and unpaid work 5% of the time.
On other websites, answering is 95% of the times unpaid work and 5% of the time boring.
Also reading questions on worlduilding is learning while having fun, schools should be like that, it's object oriented studying... while reading questions on other websites is normal textbook studying, you forget most of what you read anyway.
Yet I still remember answers I have read in this website 5-7 years ago.