Lazy load Disqus with JQuery -- Murat Corlu's method.

disqus.lazyload.js

// # Lazy load Disqus w/ Murat Corlu's method.
var disqus_div = $("#disqus_thread");
if (disqus_div.size() > 0) {
  var disqus_loaded = false,
    // Where to start loading
    top = disqus_div.offset().top,
    disqus_data = disqus_div.data(),
    check = function() {
      if (!disqus_loaded && $(window).scrollTop() + $(window).height() > top) {
        disqus_loaded = true;
        for (var key in disqus_data) {
          if (key.substr(0, 6) == 'disqus') {
            // Get Disqus parameters via data attributes
            window['disqus_' + key.replace('disqus', '').toLowerCase()] = disqus_data[key];
          }
        }
        var dsq = document.createElement('script');
        dsq.type = 'text/javascript';
        dsq.async = true;
        dsq.src = 'http://' + window.disqus_shortname + '.disqus.com/embed.js';
        (document.getElementsByTagName('head')[0] || document.getElementsByTagName('body')[0]).appendChild(dsq);
      }
    };
  $(window).scroll(check);
  check();
}