So say you had a site like StackExchange. Now imagine you created a machine-writeable API capable of posting questions and comments and doing everything your browser can do.
Of course, about 5 minutes after launching, you'd have so much spam that you would probably have ran out of room on your database servers and will have been permanently blacklisted from every search engine(except for maybe Ask :) )
So, how can you avoid that spam, while allowing a machine to actually use your API(and/or have automation involved? Is it possible in this day and age? I'd expect there is a human moderator at the end of it, but how do you cut down on the majority of spam to measures capable of being handled by human moderators?