"Is {insert whatever social platform "name" here} going to be data mined?" YES.
But since you are the sole responsible entity of your own account, with anonymity if you so wish to keep it. want something more private that it is impossible to be hacked? stay quiet and say nothing. don't speak. shhh. forever. keep it in your head then.
otherwise join ANOTHER of billions yet to come social platforms coming to a train near you.