Thanks for your comment.

I think the problem is that Steem is such a rich picking ground for spam - it's tailor made. They no longer have to entice you somewhere else to buy anything - they can make money immediately.

If an algorithm can automatically flag spam (at least in the comments it'd be a start), then I think the extra work on the blockchain would be worth it.

Spam will increase exponentially with the rise in users on the system - and is probably growing faster than "real users" already.