I describe Steemit as "a social media platform where the participants are rewarded instead of a hosting company"

I describe Steem as "a high-performance public blockchain that supports one of the largest social media sites where the participants are rewarded instead of a hosting company"

Yes, of course there is more to the story, more usages, etc. But elevator pitches must be in terms the audience understands and appreciates, so they want to ask more.