It probably eliminates 90% of it for 90% of websites, like off-the-shelf spamware hitting your blog's comments. The prevention measure you create for the remai

It probably eliminates 90% of it for 90% of websites, like off-the-shelf spamware hitting your blog's comments. The prevention measure you create for the remaining 10% (like a moderation queue + human review if you can afford it) is likely to only work because its workload is diminished 90% by a crude measure like ReCaptcha. Your dismissal doesn't illuminate anything. It turns out that abuse prevention is hard and costly.