gistfile1.txt

$.ajax({
    dataType: 'jsonp',
    jsonp: 'callback',
    url: 'http://search.twitter.com/search.json?q=%23fwgangnamstyle',
    success: function(obj) {
      for (var i = 0; i <= obj.results.length - 1; ++i) {
        var user = obj.results[i].from_user;
        var tweet_text = obj.results[i].text.replace(/#[\w\d]+/g, "<a href=\"https://twitter.com/$&\" target=\"_blank\">");
        var html = "<li><a href=https://twitter.com/" + user + ">@" + user + "</a> said " + tweet_text + "</li>"; 
        console.log(obj.results[i]);
        $("#tweet-feed ul").append(html);
      };
    }, 
});

Replace :
var tweet_text = obj.results[i].text.replace(/#[\w\d]+/g, "<a href="https://twitter.com/$&\" target="_blank">");
With :
var tweet_text = obj.results[i].text.replace(/#[\w\d]+/g, "<a href="https://twitter.com/$&\" target="_blank"> $& ");