I don't know if this is a "Steemit Killer"
More like all these new platforms on blockchains with more user empowerment are facebook killers.
For example, onG.Social is a new social media dashboard that integrates other platforms including Steemit (so you can get paid twice)
onG ICO starts today at ongcoin.io
I like ONG social as a platform. We can chose what we can watch as aDS and we get paid for it. Also there is no censorship. The company is legit and is here to stay. I will be holding ONGcoin for long