Para esto solo tenéis que el a, diseño- añadir un gadget -HTML-JAVASCRIPT , podéis modificar, el alto, ancho, colores y poner la url de vuestro blog.
CÓDIGO
<marquee direction="up" scrollamount="3" style="background- text-align: left; width:150%;height:240px;border:0px solid #000000;padding:3px" onmouseover="this.scrollAmount='3'" onmouseout="this.scrollAmount='3'">
< br/><style type="text/css"></style>
< script type="text/javascript">
//<![CDATA[
// Recent Comments Settings
var
numComments = 15,
showAvatar = true,
avatarSize = 40,
roundAvatar = false,
characters = 60,
showMorelink = false,
moreLinktext = "More »",
defaultAvatar = "https://lh3.googleusercontent.com/-RIC-7Z86S0E/UPYX-7IVLuI/AAAAAAAABTk/qx1fLgBjaJk/s40/user.png",
hideCredits = true;
//]]>
< /script>
< script type="text/javascript" src="http://widgets.way2blogging.org/blogger-widgets/w2b-recent-comments-gravatar.js"></script>
< script type="text/javascript" src="URL DE TU BLOG/feeds/comments/default?alt=json&callback=w2b_recent_comments&max-results=15"></script></marquee>
< style type="text/css">
ul.w2b_recent_comments{list-style:none;margin:0 0 15px 0;padding:0;background:#f3f3f3;border:1px solid #DAFBE9;outline:thin solid #08F677; width:100%}
.w2b_recent_comments li{background:#C8FCE0!important;padding:3px !important;display:block;clear:both;overflow:hidden;list-style:none;margin:5px;border:1px solid #14EB78; outline:
thin solid #DAFBE9}.w2b_recent_comments li .avatarImage{padding:2px;background:#fff;border:1px solid #e7e7e7;float:left;margin:0 4px 7px 3px;position:relative;overflow:hidden}
.w2b_recent_comments li img{padding:0px;position:relative;overflow:hidden;display:block}.w2b_recent_comments li span{text-shadow:1px 1px 1px #fff;margin-top:4px;color: #666;display: block;font-size: 12px;font-style: italic;padding:2px 0 6px 0;line-height: 1.2}
.w2b_recent_comments li a{color:#1f9495;text-shadow:1px 1px 1px #fff}.w2b_recent_comments li a:hover{margin-left:4px;}
< /style>
