That is something I wrote about in the past although few on here seemed to agree with me.
I would think the easiest way for @dan to do it would be to fork STEEM and then airdop tokens how he wanted (ie capping it at 50K or 100K SP) and then doing what he wants with the blockchain.
Others said he already has some stuff up in github that will be part of his social media site.
At this point, @dan's plans are a great unknown.