Hack to show comments box in sidebar.

1 Go to Layout

2 Add Feed widget. In feed url enter....

http://Your-Blog-url.blogspot.com/feeds/comments/full

in title write recent comment

save it.

3 Go to edit HTML and tick Expand widget Template.

Search for </head> and add below lines above it.

<script src='http://lasvak.googlepages.com/recent-comment.js' type='text/javascript'/>

4 Find newly added widget it will be something like this..

<b:widget id='Feed2' locked='false' title='Recent comments' type='Feed'>

and Replace it with code in below box

<b:widget id='Feed2' locked='false' title='Recent comments' type='Feed'>
<b:includable id='main'>
<h2><data:title/></h2>
<div class='widget-content'>
<ul expr:id='data:widget.instanceId + "_feedItemListDisplay"'>
<b:loop values='data:feedData.items' var='i'>
<li>
<b:if cond='data:showItemDate'>
<b:if cond='data:i.str_published != ""'>
<span class='item-date'>
On&#160;<data:i.str_published/>
</span>
</b:if>
</b:if>
<b:if cond='data:showItemAuthor'>
<b:if cond='data:i.author != ""'>
<span class='item-author'>
&#160;- <data:i.author/> commented on
</span>
</b:if>
</b:if>
<script type='text/javascript'>getPostTitle(&quot;<data:i.alternate.href/>&quot;)</script>&#160;:
<span class='item-title'>
<data:i.title/>&#160;<script type='text/javascript'>getCommentLink(&quot;<data:i.alternate.href/>&quot;)</script>
</span>
</li>
</b:loop>
</ul>
<b:include name='quickedit'/>
</div>
</b:includable>
</b:widget>

Save template. You are done.