<p>I think the biggest factor that allows SO to function is that there are <em>a lot</em> more people contributing answers and working to maintain the site.  That is, the number of people asking is larger, but the site as a whole maintains some sort of balance between the number of askers and the number of active answerers.  It seems that we are slipping out of balance, which I take to be @Glen_b's concern (although it may be just a seasonal effect, as @whuber <a href="https://stats.meta.stackexchange.com/questions/2242/are-we-seeing-a-dramatic-drop-in-answers-per-question#comment6239_2242">noted</a>).  </p>

<p>Other than that, my impression is that SO has evolved to become a loose federation of tag-based fiefdoms.  I occasionally look at the <code>[r]</code> tag page on SO, @NickCox and @StasK only follow the <code>[stata]</code> tag page, etc.  I'm sure there is some overlap for some of the tags (e.g., <code>[html]</code>, <code>[css]</code>, <code>[php]</code>, and [<code>javascript]</code> logically go together), but you still have semi-isolated islands in an archipelago.  I certainly never follow the main page on SO and I suspect (almost?) no one does.  </p>

<p>Here, on the other hand, I do follow the main page, and I'm glad I do.  This has exposed me to a lot of statistical (ML, etc.) topics that I'm still not expert in but would otherwise be totally unfamiliar with.  This has been quite valuable to me and I'm glad it remains manageable; I rue the day when it ceases to be.  </p>
