I have already written an article on a method to create popular posts widget for Blogger . This widget is not working anymore . So here is an alternate method to implement popular posts on Blogger .
As said in the previous post about popular posts widget , here also it uses the comments to differentiate the popular posts .
<script type="text/javascript">function pipeCallback(obj) {document.write('<ol style="text-transform: capitalize;">');var i;for (i = 0; i < obj.count ; i ){var href = "'" obj.value.items[i].link "'";var item = "<li>" "<a href=" href ">" obj.value.items[i].title "</a> </li>";document.write(item);}document.write('</ol>');}</script><script src="http://pipes.yahoo.com/pipes/pipe.run?_render=json&_callback=pipeCallback&_id=1a1c6e4e6d4f148e3650fda46910e15f&url=http%3A%2F%2Fwww.yoursite.com&num=10" type="text/javascript"></script><span style="font-size: 80%">widget by <a href="http://www.techknowl.com">techknowl </a></span>
Open your Blogger template’s Layout section and then select to add a new HTML/JavaScript ,through gadgets .Copy the Blogger popular posts widget code to the box and save the settings .Change www.yoursite.com with your blog URL and the value 10 with required number of popular posts .

not working for me
Hello, you might want to check the Most Popular Posts Widget I've created for blogger. A friendly tutorial to make this widget works using Yahoo Pipes.
and find the widget.
Hi BloggerGeeze,
You might want to add a link to that post so that people can actually check out your link.
LOL @ nycxs
not working this one anymore.
Now Blogger has officially added its OWN POPULAR POSTS WIDGET !