On one hand, I completely support the idea of a blacklist API designed to help clean up the Steem ecosystem, but the sceptic in me who challenges the status quo and questions things not as they are seen, but from alternative perspectives is concerned.
Steem is touted as this democratic free speech platform and as we've seen with Facebook deciding what content is deemed to conform to their guidelines is this not the exact same thing? You as a witness, on one hand, maintain the Steem blockchain and help process transactions, and while I realise witnesses such as yourself are more hands-on with Steem, who is policing the police here?
A theoretical for you: if for whatever reason you find yourself on one or more of these blacklists (you as in @themarkymark) because you own the tool, you could theoretically make yourself immune to being listed, right?
I am not saying that you would, I am saying that you could or am I misunderstanding how this all works? Am I correct in understanding that your API service is processing other lists and then providing a convenient wrapper service to offer a streamlined singular endpoint for blacklisted users?
What protections are in place to ensure that users are not incorrectly being added to these blacklists? Who are we to say what is content that should be penalised and what isn't? I realise spam, abuse, illegal content and plagiarism are big no-nos, but what about other forms of questionable content?
I've seen large users like berniesanders engage in flag wars with other users, all because he disagrees with them or has an agenda (sometimes it's justified).
I have also seen him recently make accusations against other users for stealing his ideas, as in he believes what he posts is unique and nobody else can post similar content (which is insane, because ideas cannot be owned and are not unique).
One man's blacklistable offence is another man's content. I think Bernie is a good example (this is not an attack on him, he is just a good example) because he has a witness account, he has a powerful personal account and numerous proxy voting accounts.
I get that the intention (at least in your eyes) is for bot owners to prevent blacklisted people using paid-for bidbots. But given this is an open platform, theoretically, there is nothing stopping non-bidbot users from using this for other purposes either.
I also realise nothing can be deleted by your API, content will always be on Steem. However, when something is flagged beyond visibility it's as good as deleted (I rarely show hidden posts when I see them).
I also have seen third-party bots that automatically flag blacklisted users, which presumably your API will be used for. So even if a user gets blacklisted and tries to redeem themselves until they're off, they'll potentially continue to be flagged. This affects your ability to grow and earn on Steem, it's censorship.
I think talking about what protections there will be against brigading and false blacklisting is definitely the next step you should take. This seems like a tool with noble intentions but goes against the ethos on the Steem brochure: a censorship resistance content platform.