I'd be interested in an algorithm that sorted humans from bots and gave accounts a kind of real human score. How many apps so they use? Bio data to from input devices like phones, range of non automated behaviors. Something very hard to fake.
I follow a company called Biocatch which does invisible security for banks. Their systems are proprietary and patented but worth reading their public details.
There has been a system for reliably identifying spam and bots on Steem for a long time, but it's creator @andybets left STEEM for EOS and didn't reply to my messages when I tried to contact him last time.
That is incredibly useful. What a pity it's defunct. The issue with this kind of system is that it really needs to be somewhat closed source and the algorithms hidden to prevent reverse engineering.