Check this out from Erik Verlinde.  Gravity as an emergent property.  I hope this ends up being on the right track, as I have had doubts about the existence of dark matter for quite some time.

https://astronomynow.com/2016/11/08/new-theory-of-gravity-might-explain-dark-matter/

Oh boy.  Here we go.  Another article on the same subject.  This really ought to stir some discussion at least.
https://www.quantamagazine.org/20161129-verlinde-gravity-dark-matter/

Hmmm, I'm going to have to go look at the "holographic universe" stuff from t' Hooft and Susskind before figuring that out. I had more or less glossed over it when I first encountered it because it didn't sit right, but we'll see. Anyone have a favourite primer?

You mean besides Dick and Jane and Spot?  :-)

No, not off hand.  I have yet to see an understandable explanation of the holographic universe idea.  And I agree it's probably necessary to understand Verlinde.  But, I'll check again.  If I see anything promising, I'll post it here.

If there is a version of Dick and Jane and Spot that explains the holographic universe, I will buy the hell out of that **** :)

A very good lecture from Erik Verlinde at the Perimeter Institute.  I think you should all give it a listen.  It's about an hour.

A New View on Gravity and the Dark Side of the Cosmos

And now even further analyses (see the link below) that lean toward a scale invariance of empty space which eliminates the need for both dark matter and dark energy. 

It looks like we're finally catching up to the dual Cheshire Cats of dark matter and dark energy.

Do Dark Matter and Dark Energy Exist?

That was a pretty interesting lecture. I liked the observation that things get recast in terms of current technology, though I think that may have undercut his point a little bit, since the background implication to this is that information theory will give way to something else in the next century :)

Is it common to tie theories back to string theory? Seems a bit throwaway to mention when certain concepts come from string theory. Maybe there's a theoretical tie in with the holographic theories, but it seems a bit specious.

(I still can't shake the question "how do black holes complete forming if time would come to a stop at the event horizon?" but most folks don't seem to have that issue :) )

I'm glad they're exploring different concepts. The Perimeter Institute seems to be a bit better than some for allowing breadth of approaches (Lee Smolin is there, for example) and I imagine they get fed some great minds from nearby Waterloo (a friend of mine graduated from a program there - their theoretical programs are insane! :) )

Still early days for his approach. We'll see how it pans out, though some of the thing he bases it on are necessities brought on by other hypotheses, and they may still not be necessary.