I have to wonder how accurately you could tag spammers using sentence structure and spelling analysis.

Probably not well enough to use in an automated system, but perhaps well enough to be used merely to flag things for careful/further inspection.

They are also very relentless, trying again and again for several months

That's one of the most perplexing aspects for me; how much effort some people put into getting "a quick buck." If only they'd put that much energy into something productive, they'd be way ahead.

I was first struck with this thought in highschool; the time and thought and preparation applied to cheating at exams. Half that effort applied to just reading the cartoonish textbooks would give a pass.

This effect explains most of the vitriolic anti-google commenters on HN.

Personally I've seen more vitriol and misplaced anger from pro-Google commenters.