It is for twitter as it is stated in the widget: "Tweets tagged with #todayilearned"
# sampletv.erb
<li data-row="1" data-col="1" data-sizex="2" data-sizey="1">
<div data-id="twitter_mentions" data-view="Comments" style="background-color:#ff9618;" data-moreinfo="Tweets tagged with #todayilearned"></div>
<i class="icon-twitter icon-background"></i>
</li>
Related job script is jobs/twitter.rb
also you can check in github: https://github.com/Shopify/dashing/blob/master/templates/project/jobs/twitter.rb
data-id
is twitter_mentions
, it was matched, due to environment, I can't test it so far.