I don’t know that “heliumpunk” qualifies necessarily as a new subgenre, but it is an interesting idea. As I understand it, it’s essentially a more realistic twist on steampunk, not simply tossing outmoded forms of technology into a futuristic setting, but envisioning a future in which those forms could theoretically come back into fashion:
“A future or near-future setting where anachronistic and obsolete technology is given a new lease on life, not just because it is cool, but for plausible reasons within the setting.”
Like I said, it’s an interesting idea.
Via Warren Ellis.