As a new user I don't think I have a strong enough feel for what's underrepresented. Here's my initial impressions.

1) What's really compelling to me about this website is the variety of topics covered. There's a breadth and depth of things i don't normally find and wouldn't pursue on my own. If this site got bogged down too much in any one particular area, I might stop using it. Like a certain other news site that leans too heavily toward feel-good STEMy stuff.

2) I'm way more interested in on-the-ground things people are doing in their local communities than the circus that is the electoral cycle. I've already blocked #sillyseason. The political system has near nil credibility at this point.

3) Current events, but not in the typical play-by-play, news cycle way. The site seems somewhat oriented in that direction already, just not in a self-conscious kind of way. Maybe a tag is the way forward for this, say, #newsanalysis .

4) Stuff that is challenging, but not pretentious. Critical Theory is so compelling, but the jargon that so many of those authors and their readership use tends to be impenetrable.