Themarkymark is serious about STEEM.
He either bought into it or is a preminer whom secretly transferred his STEEM, via an exchange account, from one of the secretive and private preminer accounts, to his more public account.
He is the most responsive witness that I encountered.
He obviously benefits out of STEEM:
Author rewards, curation rewards, comment_benefactor_rewards (from steemflagrewards, a group he uses to comment farm while downvoting others) and producer rewards from his hustle as a witness.
I also noticed 2 more sources to his STEEM fortune:
I believe that his financial benefits off STEEM surpass what is recorded on the blockchain, because he is so serious, dedicated, versatile in his STEEM activity, and because he had quite a fortune to begin with in order to put it into STEEM and to finance his not so successful campaign as a witness.
To run witness nodes as his, costs Federal Reserve dollars, and these dollars he mostly gets from resources other than selling his STEEM and SBDs.
The question that rises is: what pays for his living costs and STEEM witnessing costs?
Social security does not pay enough for his level of STEEM activity.
He seems to treat STEEM as a job, so it may be a job for him, and he is paid by some entity.
He may be some entrepreneur whom earns "passive income" from some businesses, and whom can allow himself to treat his STEEM hobby so serious, that it became his "nine to five" job, with added extra hours.
Did he ever elaborate about his businesses?
AFAIK, he did not.
Keeps his businesses private.
Why so? And what pays for his activity?
Why not ipromote those businesses, since he can?