Something that’s oddly more articulated in German speaking circles (though there may be significant shady undercurrents in German speaking and perhaps Nordic cultures, as far as I’ve assumed), the dark scene according to this post encompasses significantly more. To sum it up, there are several communities under this banner, some more accessible than others and those more widely known in the mainstream are emo punk music and old school Goth music.
Like I said before, the major salient difference between Goth and Emo’s that the latter hasn’t gone this far at least thematically and sartorially speaking so is thus readily understood by the mainstream. The Goth scene proper however has things that would offend the general public. (Emo’s not necessarily any more offensive but I don’t think emo music’s doesn’t seem so openly indebted to the supernatural, at least not to the same extent.) Both of them evolved from punk rock.
But Goth as a moniker and sensibility has developed an identity of its own, especially as a subculture. It’s not that emo hasn’t done the same but that of all the subcultures/genres that evolved from punk, I have the feeling that it’s Goth that’s gone the furthest. However oddly enough according to that very post, both punk and heavy metal are part of the dark scene or at least some genres are. No surprise as there could be a lot of cross-pollination.
(There might be emo bands that do take inspiration from 80s new wave and post punk and might even be the direct heirs in this regard.)
It may also be parsimonious to say that for some odd reason, punk’s rather prone to creating a lot of those dark-clad apparently emotionally minded bands/music (I suspect it probably gets tiring doing politically minded lyrics that even the Clash and Johnny Rotten would come to do similar stuff at some point). Though similar sensibilities could also play into account how and why the dark scene came to be.