Tutorial Como poner Post Relacionados en Blogger

<script type='text/javascript'>
//<![CDATA[

var relatedTitles = new Array();
var relatedTitlesNum = 0;
var relatedUrls = new Array();

function related_results_labels(json) {
for (var i = 0; i < json.feed.entry.length; i++) {
var entry = json.feed.entry[i];
relatedTitles[relatedTitlesNum] = entry.title.$t;
for (var k = 0; k < entry.link.length; k++) {
if (entry.link[k].rel == 'alternate') {
relatedUrls[relatedTitlesNum] = entry.link[k].href;
relatedTitlesNum++;
break;
}
}
}
}

function removeRelatedDuplicates() {
var tmp = new Array(0);
var tmp2 = new Array(0);
for(var i = 0; i < relatedUrls.length; i++) {
if(!contains(tmp, relatedUrls[i])) {
tmp.length += 1;
tmp[tmp.length - 1] = relatedUrls[i];
tmp2.length += 1;
tmp2[tmp2.length - 1] = relatedTitles[i];
}
}
relatedTitles = tmp2;
relatedUrls = tmp;
}

function contains(a, e) {
for(var j = 0; j < a.length; j++) if (a[j]==e) return true;
return false;
}

function printRelatedLabels() {
var cuantosPosts = 0;
var r = Math.floor((relatedTitles.length - 1) * Math.random());
var i = 0;
var dirURL = document.URL;
document.write('<ul>');
while (i < relatedTitles.length && i < 20) {
if (relatedUrls[r] != dirURL) {
document.write('<li><a href="' + relatedUrls[r] + '" title="Post relacionado: '
+ relatedTitles[r] + '">' + relatedTitles[r] + '</a></li>');
}
if (r < relatedTitles.length - 1) {
r++;
} else {
r = 0;
}
i++;
cuantosPosts++;
if (cuantosPosts == 5) {
break;
}
}
document.write('</ul>');
}

//]]>
</script>

<b:loop values='data:post.labels' var='label'>

<b:if cond='data:blog.pageType == "item"'>
<script expr:src='"/feeds/posts/default/-/" + data:label.name +
"?alt=json-in-script&callback=related_results_labels&max-results=10"'
type='text/javascript'/>
</b:if>

<div class='post-footer-line post-footer-line-3'>

<b:if cond='data:blog.pageType == "item"'>
<div class='post-footer-line post-footer-line-4' id='relpost'>
<h3>[B]Entradas relacionadas:[/B]</h3>
<b:if cond='data:blog.pageType == "item"'>
<script type='text/javascript'>
removeRelatedDuplicates();
printRelatedLabels();
</script>
</b:if>
</div></b:if>