This is seen on many boards like this:
However you can achieve somewhat similar results easy.
In message_macros added the following:
Add the following to Extra.less:
You'll have to further tweaking this to your liking.

However you can achieve somewhat similar results easy.
In message_macros added the following:
PHP:
arg-itemProp="">
<xf:set var="$monthsOld">{{ number(($xf.time - $user.register_date) / (60 * 60 * 24 * 30)) }}</xf:set>
<xf:set var="$yearsOld">{{ number(($xf.time - $user.register_date) / (60 * 60 * 24 * 30 * 12)) }}</xf:set>
<section class="message-user"
PHP:
arg-valueClass="pairs pairs--justified" />
</xf:if>
</xf:if>
</xf:contentcheck>
<xf:if is="$yearsOld >= '1'">
<div class="service-tag type-year-{$yearsOld}"><i class="fa fa-star" aria-hidden="true"></i> {$yearsOld} years of service</div>
<xf:elseif is="$monthsOld >= '1'" />
<div class="service-tag type-month-{$monthsOld}"><i class="fa fa-star" aria-hidden="true"></i> {$monthsOld} months of service</div>
</xf:if>
</div>
</xf:if>
</xf:if>
<span class="message-userArrow"></span>
Add the following to Extra.less:
CSS:
.type-month-1,
.type-month-2,
.type-month-3,
.type-month-4,
.type-month-5,
.type-month-6,
.type-month-7,
.type-month-8,
.type-month-9,
.type-month-10,
.type-month-11
{
color: hsl(199, 100%, 54%);
border-bottom-style: solid;
border-width: 2px;
}
.service-tag {
order: 9;
width: 85%;
padding: 4px 6px;
text-align: center;
border-radius: 1px;
font-size: 11px;
text-shadow: none;
text-transform: uppercase;
margin: 3px auto 0 auto;
margin-bottom: 5px;
font-weight: bold;
background: hsl(0, 0%, 7%);
}
You'll have to further tweaking this to your liking.